Pyrazolo[3,4-d]pyrimidine derivatives and their use as purinergic receptor antagonists

ABSTRACT

Use of a compound of formula (I): wherein R 1  is selected from alkyl, alkoxy, aryloxy, alkylthio, arylthio, aryl, halogen, CN, NR 6 R 7 , NR 5 COR 6 , NR 5 CONR 6 R 7 , NR 5 CO 2 R 8  and NR 5 SO 2 R 8 ; R 2  is selected from heteroaryl attached via an unsaturated carbon; R 3  is selected from H, alkyl, halogen, OR 5 , SR 5  and NR 6 R 7 ; R 4  is selected from H, acyclic alkyl, CONR 6 R 7 , CONR 5 NR 6 R 7 , COR 6 , CO 2 R 8  and SO 2 R; R 5 , R 6  and R 7  are independently selected from H, alkyl and aryl, or where R 6  and R 7  are in an NR 6 R 7  group, R 6  and R 7  may be linked to form a heterocyclic group, or where R 5 , R 6  and R 7  are in a (CONR 5 NR 6 R 7 ) group, R 5  and R 6  may be linked to form a heterocyclic group; and R 8  is selected from alkyl and aryl, or a pharmaceutically acceptable salt thereof or prodrug thereof, in the treatment or prevention of a disorder in which the blocking of purine receptors, particularly adenosine receptors and more particularly A 2A  receptors, may be beneficial, particularly wherein said disorder is a movement disorder such as Parkinson&#39;s disease or said disorder is depression, cognitive or memory impairment, acute or chronic pain, ADHD or narcolepsy, or for neuroprotection in a subject; compounds of formula (I) for use in therapy; and novel compounds of formula (I) per se.

[0001] The present invention relates to pyrazolo[3,4-d]pyrimidinederivatives and their use in therapy. In particular, the presentinvention relates to the treatment of disorders in which the reductionof purinergic neurotransmission could be beneficial. The inventionrelates in particular to the blockade of adenosine receptors andparticularly adenosine A_(2A) receptors, and to the treatment ofmovement disorders such as Parkinson's disease.

[0002] Movement disorders constitute a serious health problem,especially amongst the elderly sector of the population. These movementdisorders are often the result of brain lesions. Disorders involving thebasal ganglia which result in movement disorders include Parkinson'sdisease, Huntington's chorea and Wilson's disease. Furthermore,dyskinesias often arise as sequelae of cerebral ischaemia and otherneurological disorders.

[0003] There are four classic symptoms of Parkinson's disease: tremor,rigidity, akinesia and postural changes. The disease is also commonlyassociated with depression, dementia and overall cognitive decline.Parkinson's disease has a prevalence of 1 per 1,000 of the totalpopulation. The incidence increases to 1 per 100 for those aged over 60years. Degeneration of dopaminergic neurones in the substantia nigra andthe subsequent reductions in interstitial concentrations of dopamine inthe striatum are critical to the development of Parkinson's disease.Some 80% of cells from the substantia nigra need to be destroyed beforethe clinical symptoms of Parkinson's disease are manifested.

[0004] Current strategies for the treatment of Parkinson's disease arebased on transmitter replacement therapy (L-dihydroxyphenylacetic acid(L-DOPA)), inhibition of monoamine oxidase (e.g. Deprenyl®), dopaminereceptor agonists (e.g. bromocriptine and apomorphine) andanticholinergics (e.g. benztrophine, orphenadrine). Transmitterreplacement therapy in particular does not provide consistent clinicalbenefit, especially after prolonged treatment when “on-off” symptomsdevelop, and this treatment has also been associated with involuntarymovements of athetosis and chorea, nausea and vomiting. Additionallycurrent therapies do not treat the underlying neurodegenerative disorderresulting in a continuing cognitive decline in patients. Despite newdrug approvals, there is still a medical need in terms of improvedtherapies for movement disorders, especially Parkinson's disease. Inparticular, effective treatments requiring less frequent dosing,effective treatments which are associated with less severe side-effects,and effective treatments which control or reverse the underlyingneurodegenerative disorder, are required.

[0005] Blockade of A₂ adenosine receptors has recently been implicatedin the treatment of movement disorders such as Parkinson's disease(Richardson, P. J. et al., Trends Pharmacol. Sci. 1997, 18, 338-344) andin the treatment of cerebral ischaemia (Gao, Y. and Phillis, J. W., LifeSci. 1994, 55, 61-65). The potential utility of adenosine A_(2A)receptor antagonists in the treatment of movement disorders such asParkinson's Disease has recently been reviewed (Mally, J. and Stone, T.W., CNS Drugs, 1998, 10, 311-320).

[0006] Adenosine is a naturally occurring purine nucleoside which has awide variety of well-documented regulatory functions and physiologicaleffects. The central nervous system (CNS) effects of this endogenousnucleoside have attracted particular attention in drug discovery, owingto the therapeutic potential of purinergic agents in CNS disorders(Jacobson, K. A. et al., J. Med Chem. 1992, 35, 407-422). Thistherapeutic potential has resulted in considerable recent researchendeavour within the field of adenosine receptor agonists andantagonists (Bhagwhat, S. S.; Williams, M. Exp. Opin. Ther. Patents1995, 5,547-558).

[0007] Adenosine receptors represent a subclass (P₁) of the group ofpurine nucleotide and nucleoside receptors known as purinoreceptors. Themain pharmacologically distinct adenosine receptor subtypes are known asA₁, A_(2A), A_(2B) (of high and low affinity) and A₃ (Fredholm, B. B.,et al., Pharmacol. Rev. 1994, 46, 143-156). The adenosine receptors arepresent in the CNS (Fredholm, B. B., News Physiol. Sci., 1995, 10,122-128).

[0008] The design of P₁ receptor-mediated agents has been reviewed(Jacobson, K. A., Suzuki, F., Drug Dev. Res., 1997, 39, 289-300;Baraldi, P. G. et al., Curr. Med, Chem. 1995, 2, 707-722), and suchcompounds are claimed to be useful in the treatment of cerebral ischemiaor neurodegenerative disorders, such as Parkinson's disease (Williams,M. and Burnstock, G. Purinergic Approaches Exp. Ther. (1997), 3-26.Editor: Jacobson, Kenneth A.; Jarvis, Michael F. Publisher: Wiley-Liss,New York, N.Y.)

[0009] It has been speculated that xanthine derivatives such as caffeinemay offer a form of treatment for attention-deficit hyperactivitydisorder (ADHD). A number of studies have demonstrated a beneficialeffect of caffeine on controlling the symptoms of ADHD (Garfinkel, B. D.et al., Psychiatry, 1981, 26, 395-401). Antagonism of adenosinereceptors is thought to account for the majority of the behaviouraleffects of caffeine in humans and thus blockade of adenosine A_(2A)receptors may account for the observed effects of caffeine in ADHDpatients. Therefore a selective A_(2A) receptor antagonist may providean effective treatment for ADHD but without the-unwanted. side-effectsassociated with current therapy.

[0010] Adenosine receptors have been recognised to play an importantrole in regulation of sleep patterns, and indeed adenosine antagonistssuch as caffeine exert potent stimulant effects and can be used toprolong wakefulness (Porkka-Heiskanen, T. et al., Science, 1997, 276,1265-1268). Recent evidence suggests that a substantial part of theactions of adenosine in regulating sleep is mediated through theadenosine A_(2A) receptor (Satoh, S., et al., Proc. Natl. Acad. Sci.,USA, 1996). Thus, a selective A_(2A) receptor antagonist may be ofbenefit in counteracting excessive sleepiness in sleep disorders such ashypersomnia or narcolepsy.

[0011] It has recently been observed that patients with major depressiondemonstrate a blunted response to adenosine agonist-induced stimulationin platelets, suggesting that a dysregulation of A_(2A) receptorfunction may occur during depression (Berk, M. et al, 2001, Eur.Neuropsychopharmacol. 11, 183-186). Experimental evidence in animalmodels has shown that blockade of A_(2A) receptor function confersantidepressant activity (El Yacoubi, M et al. Br. J. Pharmacol. 2001,134, 68-77). Thus, A_(2A) receptor antagonists may offer a novel therapyfor the treatment of major depression and other affective disorders inpatients.

[0012] The pharmacology of adenosine A_(2A) receptors has been reviewed(Ongini, E.; Fredholm, B. B. Trends Pharmacol. Sci. 1996, 17(10),364-372). One potential underlying mechanism in the aforementionedtreatment of movement disorders by the blockade of A₂ adenosinereceptors is the evidence of a functional link between adenosine A_(2A)receptors to dopamine D₂ receptors in the CNS. Some of the early studies(e.g. Ferre, S. et al., Stimulation of high-affinity adenosine A₂receptors decreases the affinity of dopamine D₂ receptors in ratstriatal membranes. Proc. Natl. Acad. Sci. U.S.A. 1991, 88, 7238-41)have been summarised in two more recent articles (Fuxe, K. et al.,Adenosine Adenine Nucleotides Mol. Biol. Integr. Physiol., [Proc. Int.Symp.], 5th (1995), 499-507. Editors: Belardinelli, Luiz; Pelleg, Amir.Publisher: Kluwer, Boston, Mass.; Ferre, S. et al., Trends Neurosci.1997, 20, 482-487).

[0013] As a result of these investigations into the functional role ofadenosine A_(2A) receptors in the CNS, especially in vivo studieslinking A₂ receptors with catalepsy (Ferre et al., Neurosci. Lett. 1991,130, 162-4; Mandhane, S. N. et al., Eur. J. Pharmacol. 1997, 328,135-141) investigations have been made into agents which selectivelybind to adenosine A_(2A) receptors as potentially effective treatmentsfor Parkinson's disease.

[0014] While many of the potential drugs for treatment of Parkinson'sdisease have shown benefit in the treatment of movement disorders, anadvantage of adenosine A_(2A) antagonist therapy is that the underlyingneurodegenerative disorder may also be treated. The neuroprotectiveeffect of adenosine A_(2A) antagonists has been reviewed (Ongini, E.;Adami, M.; Ferri, C.; Bertorelli, R., Ann. N. Y. Acad. Sci. 1997,825(Neuroprotective Agents), 30-48). In particular, compelling recentevidence suggests that blockade of A_(2A) receptor function confersneuroprotection against MPTP-induced neurotoxicity in mice (Chen, J-F.,J. Neurosci. 2001, 21, RC143). In addition, several recent studies haveshown that consumption of dietary caffeine, a known adenosine A_(2A)receptor antagonist, is associated with a reduced risk of Parkinson'sdisease in man (Ascherio, A. et al, Ann Neurol., 2001, 50, 56-63; Ross GW, et al., JAMA, 2000, 283, 2674-9). Thus, A_(2A) receptor antagonistsmay offer a novel treatment for conferring neuroprotection inneurodegenerative diseases such as Parkinson's disease.

[0015] Xanthine derivatives have been disclosed as adenosine A₂ receptorantagonists as useful for treating various diseases caused byhyperfunctioning of adenosine A₂ receptors, such as Parkinson's disease(see, for example, EP-A-565377).

[0016] One prominent xanthine-derived adenosine A_(2A) selectiveantagonist is CSC [8-(3-chlorostyryl)caffeine] (Jacobson et al., FEBSLett., 1993, 323, 141-144).

[0017] Theophylline (1,3-dimethylxanthine), a bronchodilator drug whichis a mixed antagonist at adenosine A₁ and A_(2A) receptors, has beenstudied clinically. To determine whether a formulation of this adenosinereceptor antagonist would be of value in Parkinson's disease an opentrial was conducted on 15 Parkinsonian patients, treated for up to 12weeks with a slow release oral theophyiline preparation (150 mg/day),yielding serum theophylline levels of 4.44 mg/L after one week. Thepatients exhibited significant improvements in mean objective disabilityscores and 11 reported moderate or marked subjective improvement (Mally,J., Stone, T. W. J. Pharm. Pharmacol. 1994, 46, 515-517).

[0018] KF 17837[(E)-8-(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine] is aselective adenosine A_(2A) receptor antagonist which on oraladministration significantly ameliorated the cataleptic responsesinduced by intracerebroventricular administration of an adenosine A_(2A)receptor agonist, CGS 21680. KF 17837 also reduced the catalepsy inducedby haloperidol and reserpine. Moreover, KF 17837 potentiated theanticataleptic effects of a subthreshold dose of L-DOPA plusbenserazide, suggesting that KF 17837 is a centrally active adenosineA_(2A) receptor antagonist and that the dopaminergic function of thenigrostriatal pathway is potentiated by adenosine A_(2A) receptorantagonists (Kanda, T. et al., Eur. J. Pharmacol. 1994, 256, 263-268).The structure activity relationship (SAR) of KF 17837 has been published(Shimada, J. et al., Bioorg. Med. Chem. Lett. 1997, 7, 2349-2352).Recent data has also been provided on the A_(2A) receptor antagonistKW-6002 (Kuwana, Y et al., Soc. Neurosci. Abstr. 1997, 23, 119.14; andKanda, T. et al., Ann. Neurol. 1998, 43(4), 507-513).

[0019] New non-xanthine structures sharing these pharmacologicalproperties include SCH 58261 and its derivatives (Baraldi, P. G. et al.,Pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine Derivatives: Potent andSelective A_(2A) Adenosine Antagonists. J. Med. Chem. 1996, 39,1164-71). SCH 58261(7-(2-phenylethyl)-5-amino-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine) is reported as effective in the treatment of movementdisorders (Ongini, E. Drug Dev. Res. 1997, 42(2), 63-70) and has beenfollowed up by a later series of compounds (Baraldi, P. G. et al., J.Med Chem. 1998, 41(12), 2126-2133).

[0020] The foregoing discussion indicates that a potentially effectivetreatment for movement disorders in humans would comprise agents whichact as antagonists at adenosine A_(2A) receptors.

[0021] It has now been found that pyrazolo[3,4-d]pyrimidine derivatives,which are structurally unrelated to known adenosine receptorantagonists, exhibit unexpected antagonist binding affinity at adenosine(P₁) receptors, and in particular at the adenosine A_(2A) receptor. Suchcompounds may therefore be useful for the treatment of disorders inwhich the blocking of purine receptors, particularly adenosine receptorsand more particularly adenosine A_(2A) receptors, may be beneficial. Inparticular, such compounds may be suitable for the treatment of movementdisorders, such as disorders of the basal ganglia which result indyskinesias. Disorders of particular interest in the present inventioninclude Parkinson's disease, Alzheimer's disease, spasticity,Huntington's chorea and Wilson's disease.

[0022] Such compounds may also be particularly suitable for thetreatment of depression, cognitive or memory impairment includingAlzheimer's disease, acute or chronic pain, ADHD, narcolepsy or forneuroprotection.

[0023] According to the present invention there is provided the use of acompound of formula (I):

[0024] wherein

[0025] R₁ is selected from alkyl, alkoxy, aryloxy, alkylthio, arylthio,aryl, halogen, CN, NR₆R₇, NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈ and NR₅SO₂R₈;

[0026] R₂ is selected from heteroaryl attached via an unsaturated carbonof said heteroaryl;

[0027] R₃ is selected from H, alkyl, halogen, OR₅, SR₅ and NR₆R₇;

[0028] R₄ is selected from H, acyclic alkyl, CONR₆R₇, CONR₅NR₆R₇, COR₆,CO₂R₈ and SO₂R₈;

[0029] R₅, R₆ and R₇ are independently selected from H, alkyl and arylor where R₆ and R₇ are in an NR₆R₇ group R₆ and R₇ may be linked to forma heterocyclic group, or where R₅, R₆ and R₇ are in a (CONR₅NR₆R₇)group, R₅ and R₆ may be linked to form a heterocyclic group; and

[0030] R₈ is selected from alkyl and aryl,

[0031] or a pharmaceutically acceptable salt or prodrug thereof, in themanufacture of a medicament for the treatment or prevention of adisorder in which the blocking of purine receptors, particularlyadenosine receptors and more particularly A_(2A) receptors, may bebeneficial.

[0032] As used herein the term “alkyl”, unless otherwise stated, means abranched or unbranched, cyclic or acyclic, saturated or unsaturated(e.g. alkenyl or alkynyl) hydrocarbyl radical which may be substitutedor unsubstituted. Where cyclic, the alkyl group is preferably C₃ to C₁₂,more preferably C₅ to C₁₀, more preferably C₅, C₆ or C₇. Where acyclic,the alkyl group is preferably C₁ to C₁₀, more preferably C₁ to C₆, morepreferably methyl, ethyl, propyl (n-propyl or isopropyl), butyl(n-butyl, isobutyl or tertiary-butyl) or pentyl (including n-pentyl andisopentyl), more preferably methyl. It will be appreciated thereforethat the term “alkyl” as used herein, unless otherwise stated, includesalkyl (branched or unbranched), alkenyl (branched or unbranched),alkynyl (branched or unbranched), cycloalkyl, cycloalkenyl andcycloalkynyl.

[0033] As used herein, the term “lower alkyl” means methyl, ethyl,propyl (n-propyl or isopropyl) or butyl (n-butyl, isobutyl ortertiary-butyl).

[0034] As used herein, the term “aryl” means an aromatic group, such asphenyl or naphthyl (preferably phenyl), or a heteroaromatic groupcontaining one or more heteroatom(s) preferably selected from N, O andS, such as pyridyl, pyrrolyl, quinolinyl, furanyl, thienyl, oxadiazolyl,thiadiazolyl, thiazolyl, oxazolyl, isoxazolyl, pyrazolyl, triazolyl,imidazolyl, pyrimidinyl, indolyl, pyrazinyl and indazolyl.

[0035] As used herein, the term “heteroaryl” means an aromatic groupcontaining one or more heteroatom(s) preferably selected from N, O andS, such as pyridyl, pyrrolyl, quinolinyl, furanyl, thienyl, oxadiazolyl,thiadiazolyl, thiazolyl, oxazolyl, isoxazolyl, pyrazolyl, triazolyl,imidazolyl, pyrimidinyl, indolyl, pyrazinyl and indazolyl.

[0036] As used herein, the term “non-aromatic heterocyclyl” means anon-aromatic cyclic group containing one or more heteroatom(s)preferably selected from N, O and S, such as a cyclic amino group(including aziridinyl, azetidinyl, pyrrolidinyl, piperidyl, piperazinyl,morpholinyl) or a cyclic ether (including tetrahydrofuranyl).

[0037] As used herein, the term “alkoxy” means alkyl-O—. As used herein,the term “aryloxy” means aryl-O—.

[0038] As used herein, the term “halogen” means a fluorine, chlorine,bromine or iodine radical.

[0039] As used herein, the term “ortho,ortho-disubstituted aryl groups”refers to heteroaryl groups which are substituted in both orthopositions of the heteroaryl group relative to the point of attachment ofthe heteroaryl group to the pyrimidine ring.

[0040] As used herein, the term “prodrug” means any pharmaceuticallyacceptable prodrug of a compound of the present invention.

[0041] Where any of R₁ to R₁₄ is selected from alkyl, alkoxy andthioalkyl, in accordance with formula (I) as defined above, then thatalkyl group, or the alkyl group of the alkoxy or thioalkyl group, may besubstituted or unsubstituted. Where any of R₁ to R₁₄ are selected fromaryl, aryloxy and thioaryl, in accordance with formula (I) as definedabove, then said aryl group, or the aryl group of the aryloxy orthioaryl group, may be substituted or unsubstituted. Where R₆ and R₇, orR₅ and R₆, are linked to form a heterocyclic group, the heterocyclicgroup may be substituted or unsubstituted. Where substituted, there willgenerally be 1 to 3 substituents present, preferably 1 substituent.Substituents may include:

[0042] carbon-containing groups such as

[0043] alkyl,

[0044] aryl, (e.g. substituted and unsubstituted phenyl (including(alkyl)phenyl, (alkoxy)phenyl, (alkyl- and aryl-sulfonylamino)phenyl andhalophenyl),

[0045] arylalkyl; (e.g. substituted and unsubstituted benzyl);

[0046] halogen atoms and halogen containing groups such as

[0047] haloalkyl (e.g. trifluoromethyl),

[0048] haloaryl (e.g. chlorophenyl);

[0049] oxygen containing groups such as

[0050] alcohols (e.g. hydroxy, hydroxyalkyl, hydroxyaryl,(aryl)(hydroxy)alkyl),

[0051] ethers (e.g. alkoxy, aryloxy, alkoxyalkyl, aryloxyalkyl,alkoxyaryl, aryloxyaryl),

[0052] aldehydes (e.g. carboxaldehyde),

[0053] ketones (e.g. alkylcarbonyl, arylcarbonyl, alkylcarbonylalkyl,alkylcarbonylaryl, arylcarbonylalkyl, arylcarbonylaryl,arylalkylcarbonyl, arylalkylcarbonylalkyl, arylalkylcarbonylaryl)

[0054] acids (e.g. carboxy, carboxyalkyl, carboxyaryl),

[0055] acid derivatives such as esters

[0056] (e.g. alkoxycarbonyl, aryloxycarbonyl, alkoxycarbonylalkyl,aryloxycarbonylalkyl, alkoxycarbonylaryl, aryloxycarbonylaryl,alkylcarbonyloxy, alkylcarbonyloxyalkyl), amides

[0057] (e.g. arinocarbonyl, mono- or di-alkylaminocarbonyl,cyclicaminocarbonyl, aminocarbonylalkyl, mono- ordi-alkylaminocarbonylalkyl, arylaminocarbonyl or arylalkylaminocarbonyl,alkylcarbonylamino, arylcarbonylamino or arylalkylcarbonylamino),carbamates

[0058] (eg. alkoxycarbonylamino, aryloxycarbonylamino,arylalkyloxycarbonylamino, aminocarbonyloxy, mono- ordi-alkylaminocarbonyloxy, arylaminocarbonyloxy orarylalkylaminocarbonyloxy) and ureas

[0059] (eg. mono- or di-alkylaminocarbonylamino, arylaminocarbonylaminoor arylalkylaminocarbonylamino);

[0060] nitrogen containing groups such as

[0061] amines (e.g. amino, mono- or dialkylamino, cyclicamino,arylamino, aminoalkyl, mono- or dialkylaminoalkyl),

[0062] azides,

[0063] nitriles (e.g. cyano, cyanoalkyl),

[0064] nitro,

[0065] sulfonamides (e.g. aminosulfonyl, mono- or di-alkylaminosulfonyl,mono- or di-arylaminosulfonyl, alkyl- or aryl-sulfonylamino, alkyl- oraryl-sulfonyl(alkyl)amino, alkyl- or aryl-sulfonyl(aryl)amino);

[0066] sulfur containing groups such as

[0067] thiols, thioethers, sulfoxides, and sulfones

[0068] (e.g. alkylthio, alkylsulfinyl, alkylsulfonyl, alkylthioalkyl,alkylsulfinylalkyl, alkylsulfonylalkyl, arylthio, arylsulfinyl,arylsulfonyl, arylthioalkyl, arylsulfinylalkyl, arylsulfonylalkyl)

[0069] and heterocyclic groups containing one or more, preferably one,heteroatom,

[0070] (e.g. thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl,thiazolyl, isothiazolyl, oxazolyl, oxadiazolyl, thiadiazolyl,aziridinyl, azetidinyl, pyrrolidinyl, pyrrolinyl, imidazolidinyl,imidazolinyl, pyrazolidinyl, tetrahydrofuranyl, pyranyl, pyronyl,pyridyl, pyrazinyl, pyridazinyl, piperidyl, hexahydroazepinyl,piperazinyl, morpholinyl, thianaphthyl, benzofuranyl, isobenzofuranyl,indolyl, oxyindolyl, isoindolyl, indazolyl, indolinyl, 7-azaindolyl,benzopyranyl, coumarinyl, isocoumarinyl, quinolinyl, isoquinolinyl,naphthridinyl, cinnolinyl, quinazolinyl, pyridopyridyl, benzoxazinyl,quinoxalinyl, chromenyl, chromanyl, isochromanyl, phthalazinyl andcarbolinyl).

[0071] Where any of R₁ to R₁₄ is selected from aryl or from anaryl-containing group such as aryloxy or arylthio, preferred substituentgroup(s) are selected from halogen, alkyl (substituted or unsubstituted;and where substituted particularly from alkoxyalkyl, hydroxyalkyl,aminoalkyl and haloalkyl), hydroxy, aloxy, CN, NO₂, amines (includingamino, mono- and di-alkylamino), alkoxycarbonyl, aminocarbonyl,carboxamido, sulfonamido, alkoxycarbonylamino and aryl, and particularlyfrom unsubstituted alkyl, substituted alkyl (including alkoxyalkyl andaminoalkyl), halogen and amines.

[0072] In one embodiment, where any of R₁ to R₁₄ is directly substitutedby an alkyl substituent group, or by an alkyl-containing substituentgroup (such as alkoxy or alkylcarbonylamino for example), then the alkylmoiety of the substituent group directly attached to any of R₁ to R₁₄may be further substituted by the substituent groups hereinbeforedescribed and particularly by halogen, hydroxy, alkoxy, CN, amines(including amino, mono- and di-alkyl amino) and aryl.

[0073] In a further embodiment, where any of R₁ to R₁₄ is directlysubstituted by an aryl substitutent group, or by an arylcontainingsubstituent group (such as aryloxy or arylaminocarbonylamino forexample), then the aryl moiety of the substituent group directlyattached to any of R₁ to R₁₄ may be further substituted by thesubstituent groups hereinbefore described and particularly by halogen,alkyl (substituted or unsubstituted; and where substituted particularlyfrom alkoxyalkyl, hydroxyalkyl, aminoalkyl and haloalkyl), hydroxy,alkoxy, CN, NO₂, amines (including amino, mono- and di-alkylamino),alkoxycarbonyl, aminocarbonyl, carboxamido, sulfonamido,alkoxycarbonylamino and aryl. In a further embodiment, said aryl moietyis substituted by halogen, alkyl (including CF₃), hydroxy, alkoxy, CN,amines (including amino, mono- and di-ailtyl amino) and NO₂. In afurther embodiment, said aryl moiety is substituted by unsubstitutedalkyl, substituted alkyl (particularly alkoxyalky and aminoalkyl),halogen and amines.

[0074] The terms “directly substituted” and “directly attached”, as usedherein, mean that the substituent group is bound directly to any of R₁to R₁₄ without any intervening divalent atoms or groups.

[0075] In the compounds of formula (I), R₁ is selected from alkyl(including branched and unbranched alkyl, substituted and unsubstitutedalkyl, and cyclic and acyclic alkyl), alkoxy, aryloxy, alkylthio,arylthio, aryl (including heteroaryl), halogen, CN, NR₆R₇ (includingNH₂, mono-alkylamino and di-alkylamino), NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈and NR₅SO₂R₈.

[0076] Where R₁ is selected from alkyl, alkoxy and alkylthio, then saidalkyl group or the alkyl group of the alkoxy or alkylthio is preferablyselected from C₁₋₆ alkyl (including branched and unbranched alkyl,substituted and unsubstituted alkyl, and cyclic and acyclic alkyl),preferably saturated C₁₋₆ alkyl, and more preferably lower alkyl. In oneembodiment, R₁ is selected from substituted alkyl, particularlyhaloalkyl (including CF₃) and arylalkyl (including heteroarylalkyl), andparticularly haloalkyl (including CF₃).

[0077] Where R₁ is selected from NR₅CONR₆R₇, NR₅COR₆, NR₅CO₂R₈ andNR₅SO₂R₈, preferably R₅ is H or alkyl, and preferably H.

[0078] It is preferred that R₁ is selected from alkyl, alkoxy,thioalkyl, NR₆R₇ (including NH₂), NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈ andNR₅SO₂R₈, and preferably from NR₆R₇ (including NH₂), NR₅COR₆,NR₅CONR₆R₇, NR₅CO₂R₈ and NR₅SO₂R₈, more preferably from NR₆R₇ (includingNH₂), and more preferably from NH₂.

[0079] In the compounds of formula (I), R₂ is substituted orunsubstituted heteroaryl attached via an unsaturated carbon atom.Preferably, the heteroaryl group is a 5- or 6-membered monocyclic group.

[0080] Preferably, R₂ is a heteroaryl group which is attached to thepyrimidine ring of formula (I) such that at least one heteroatom isadjacent to the unsaturated carbon atom attached to the pyrimidine ring.Preferably, R₂ is an N, O or S-containing heteroaryl group. R₂ maycontain one or more heteroatom(s) selected from N, O and S.

[0081] It is preferred that R₂ is not an ortho,ortho-disubstitutedheteroaryl group, and preferably R₂ is not substituted at either orthoposition. As used herein, reference to ortho-substitution of the R₂group means the ortho positions of the R₂ group relative to the point ofattachment of R₂ to the pyrimidine moiety of formula (I).

[0082] In a preferred embodiment, R₂ is selected from furyl (including2-furyl), thienyl (including 2-thienyl), pyridyl (including 2-pyridyl),thiazolyl (including 2- and 5-thiazolyl), pyrazolyl (including3-pyrazolyl), triazolyl (including 4-triazolyl), pyrrolyl (including2-pyrrolyl) and oxazolyl (including 5-oxazolyl). In a furtherembodiment, R₂ is selected from 2-furyl, 2-thienyl, 2-thiazolyl,2-pyridyl, 3-pyrazolyl, 2-pyrrolyl, 4-triazolyl and 5-oxazolyl. In afurther preferred embodiment, R₂ is selected from furyl, thienyl,pyridyl, thiazolyl and pyrazolyl, and particularly from 2-furyl,2-thienyl, 2-thiazolyl, 2-pyridyl and 3-pyrazolyl. In a furtherembodiment, R₂ is selected from furyl, thienyl and pyridyl, preferably2-furyl, 2-thienyl and 2-pyridyl. In a particularly preferredembodiment, R₂ is selected from furyl, and preferably from 2-furyl,substituted or unsubstituted.

[0083] In the compounds of formula (I), R₃ is selected from H, alkyl(including branched and unbranched alkyl, substituted and unsubstitutedalkyl, and cyclic and acyclic alkyl), halogen, OR₅, SR₅ and NR₆R₇.

[0084] Where R₃ is selected from alkyl, alkoxy and alkylthio, then saidalkyl group or the alkyl group of the alkoxy or alkylthio is preferablyselected from C₁₋₆ alkyl (including branched and unbranched alkyl,substituted and unsubstituted alkyl, and cyclic and acyclic alkyl),preferably saturated C₁₋₆ alkyl, and more preferably lower alkyl.

[0085] Preferably, R₃ is hydrogen.

[0086] In the compounds of formula (I), R₄ is selected from H, acyclicalkyl (including branched and unbranched acyclic alkyl, and substitutedand unsubstituted acyclic alkyl), CONR₆R₇, CONR₅NR₆R₇, COR₆, CO₂R₈ andSO₂R₈.

[0087] Where R₄ is selected from acyclic alkyl, R₄ is preferably C₁₋₆acyclic alkyl (including alkenyl and alkynyl). In one embodiment, R₄ isselected from C₁₋₆ saturated acyclic alkyl, preferably lower alkyl.

[0088] In one embodiment, R₄ is selected from substituted acyclic alkyl(including saturated acyclic alkyl and alkenyl). Preferred substituentsare susbtituted and unsubstituted aryl (including heteroaryl),cycloalkyl, non-aromatic heterocyclyl, CO₂R₅, CONR₆R₇, CONR₅NR₆R₇ andC(═NR₅)NR₆R₇, preferably aryl (including heteroaryl) and CONR₆R₇, morepreferably aryl (including heteroaryl).

[0089] Where R₄ is selected from acyclic alkyl substituted by aryl(including heteroaryl), the aryl (including heteroaryl) group mayunsubstituted, or substituted as defined in more detail below in respectof of the group referred to as R₁₁. Preferably, the aryl-substitutedacyclic alkyl is an aryl-substituted methyl group. Preferred aryl groupsare set out in detail below in respect of the group referred to as Ar.

[0090] In one embodiment, R₄ is selected from (CR₉R₁₀)_(n)R₁₁ wherein nis 1 to 6 (preferably n is 1, 2 or 3, more preferably n is 1), R₉ andR₁₀ are independently selected from H, alkyl and aryl, and R₁₁ isselected from aryl (including heteroaryl), cycloalkyl, non-aromaticheterocyclic, CO₂R₅, CONR₆R₇, CONR₅NR₆R₇ and C(═NR₅)NR₆R₇, wherein R₁₁is preferably aryl (including heteroaryl) or CONR₆R₇. More preferablyR₁₁ is aryl (including heteroaryl). Preferably R₉ and R₁₀ areindependently selected from H and alkyl, more preferably H.

[0091] Where R₁₁ is selected from CONR₆R₇, R₆ and R₇ are selected fromH, alkyl (including substituted alkyl such as arylalkyl (includingheteroarylalkyl)) and aryl (including heteroaryl) or R₆ and R₇ may belinked to form a heterocyclic ring. In one embodiment, R₆ and R₇ areselected from H, unsubstituted alkyl, arylalkyl (includingheteroarylalkyl) and aryl (including heteroaryl). Said aryl groups maybe substituted or unsubstituted. In a preferred embodiment one of R₆ andR₇ is hydrogen.

[0092] Where R₁₁ is aryl (including heteroaryl), the aryl (includingheteroaryl) group may be unsubstituted, or may be substituted. In oneembodiment, R₁₁ is selected from the group consisting of substitutedaryl (including heteroaryl) groups, preferably mono-, di- ortri-substituted aryl (including heteroaryl) groups represented by theformula Ar(R₁₂)_(a)(R₁₃)_(b)(R₁₄)_(c) wherein Ar is an aryl (includingheteroaryl) group; wherein R₁₂, R₁₃ and R₁₄ are substituent group(s),the same or different; and wherein a, b and c are 0 or 1 such thata+b+c≧1.

[0093] In one embodiment, the group Ar is selected from phenyl. In analternative embodiment, the group Ar is selected from heteroaryl groupssuch as those described hereinabove, preferably from mono or bicyclicheteroaryl groups, more preferably from pyridyl (including 2-pyridyl,3-pyridyl and 4-pyridyl, preferably 2-pyridyl), indolyl (including2-indolyl, 3-indolyl, 4-indolyl, 5-indolyl, 6-indolyl and 7-indolyl),furyl (including 2-furyl and 3-furyl, preferably 2-furyl), thienyl(including -2-thienyl and 3-thienyl, preferably 2-thienyl), isoindolyl,indolinyl, isoxazolyl, oxazolyl, thiazolyl, pyrazinyl, pyrimidinyl,quinolinyl, benzoxadiazolyl, benzothiadiazolyl, benzotriazolyl,indazolyl, benzodioxolyl and dihydrobenzofuranyl, more preferably frompyridyl (preferably 2-pyridyl), indolyl, furyl (preferably 2-furyl) andthienyl (preferably 2-thienyl), and most preferably from pyridyl(preferably 2-pyridyl), furyl (preferably 2-furyl) and thienyl(preferably 2-thienyl).

[0094] In one embodiment, the group Ar is selected from phenyl, pyridyl(preferably 2-pyridyl), furyl (preferably 2-furyl), thienyl (preferably2-thienyl) and indolyl, and particularly from phenyl, pyridyl(preferably 2-pyridyl), furyl (preferably 2-furyl) and thienyl(preferably 2-thienyl).

[0095] The substituent groups R₁₂, R₁₃ and R₁₄ may be selected from anyof the substituent groups described herein above.

[0096] In a preferred embodiment, R₁₂, R₁₃ and R₁₄ are selected fromNR₆R₇ (including NH₂, and NHR₆), alkyl (substituted or unsubstituted;preferably C₁₋₆ acyclic alkyl), alkoxy (including fluoroalkoxy), halogen(including F, Cl, Br and I), NO₂, CN, hydroxy, NHOH, CHO, CONR₆R₇,CO₂R₅, NR₅COR₆ (preferably NHCOR₆), NR₅CO₂R₈ (preferably NHCO₂R₈),NR₅SO₂R₈ (preferably NHSO₂R₈), OCO₂R₈ and aryl (including heteroaryl).

[0097] In a more preferred embodiment, R₁₂, R₁₃ and R₁₄ are selectedfrom NR₆R₇ (including NH₂ and NHR₆), alkyl (substituted orunsubstituted; and preferably C₁₋₆ acyclic saturated alkyl) and halogen(preferably F or Cl, particularly F).

[0098] In a parficularly preferred embodiment, R₁₂, R₁₃ and R₁₄ areselected from NR₆R₇ (including NH₂ and NHR₆, preferably NH₂) and alkyl(substituted or unsubstituted; preferably C₁₋₆ acyclic saturated alkyl;

[0099] Where R₁₂, R₁₃ and R₁₄ are selected from substituted alkyl, saidalkyl is preferably selected from alkoxyalkyl, hydroxyalkyl, aminoalkyl(including NH₂-alkyl, mono-alkylaminoalkyl and di-alkylaminoalkyl),haloalkyl particularly fluoroalkyl (including CF₃)), cyanoalkyl,alkylthioalkyl, alkylcarboxyaminoalkyl, alkoxycarbonylaminoalkyl andalkylsulfonylamino, more preferably from alkoxyalkyl, hydroxyalkyl,aminoalkyl and haloalkyl (particularly fluoroalkyl (including CF₃)) andmost preferably from alkoxyalkyl and aminoalkyl.

[0100] In one embodiment, the substituent groups R₁₂, R₁₃ and R₁₄ areselected from halogen, alkyl (including CF₃), hydroxy, alkoxy,alkylthio, CN, amines (including amino, mono- and di-alkyl amino) andNO₂.

[0101] Where the Ar group is phenyl, the phenyl ring may be mono-, di-or tri-substituted, preferably wherein the substituent group is selectedfrom NR₆R₇, alkyl, alkoxy, halogen, NO₂, CN, hydroxy, CONR₆R₇, CO₂R₅,NR₅COR₆, NR₅CO₂R₈, NR₅SO₂R₈ and OCO₂R₈, as described above, and morepreferably from NR₆R₇ (including NH₂ and NHR₆, and preferably NH₂),alkyl (substituted or unsubstituted; preferably C₁₋₆ acyclic saturatedalkyl; and, where substituted, preferably from alkoxyalkyl,hydroxyalkyl, aminoalkyl and haloalkyl particularly fluoroalkyl(including CF₃)), and more preferably from alkoxyalkyl and aminoalkyl)and halogen (preferably F or Cl, particularly F). Where (a+b+c) is 2 or3, it is preferred that at least one of the substituent groups is NR₆R₇,particularly NH₂.

[0102] Where the Ar group is pyridyl, the pyridyl group (which ispreferably a 2-pyridyl group) is preferably mono-substituted, preferably6substituted. The preferred substituent group(s) are selected from alkyl(including substituted and unsubstituted, saturated and unsaturated(such as alkenyl, including vinyl); and preferably C₁₋₆ acyclic alkyl),alkoxy, halogen, aryl, NO₂, NHOH and CHO, as described above, and morepreferably from alkyl (substituted or unsubstituted; preferably C₁₋₆acyclic saturated alkyl; and, where substituted, preferably fromalkoxyalkyl, hydroxyalkyl, aminoalkyl and haloalkyl (particularlyfluoroalkyl (including CF₃)), and more preferably from alkoxyalkyl andaminoalkyl).

[0103] Where R₄ is selected from CONR₆R₇, R₆ and R₇ are selected from H,alkyl (including substituted alkyl such as arylalkyl (includingheteroarylalkyl)) and aryl (including heteroaryl) or R₆ and R₇ may belinked to form a heterocyclic ring. In one embodiment, R₆ and R₇ areselected from H. unsubstituted alkyl, arylalkyl (includingheteroarylalkyl) and aryl (including heteroaryl). Said aryl groups maybe substituted or unsubstituted. In a preferred embodiment one of R₆ andR₇ is hydrogen. In a further preferred embodiment, R₆ is H and R₇ isselected fom arylalkyl (including heteroarylalkyl),preferably arylmethyl(including heteroarylmethyl).

[0104] In a preferred embodiment, R₄ is selected from H and substitutedacylic alkyl, preferably wherein said acyclic alkyl is substituted byaryl (including heteroaryl) or CONR₆R₇, and preferably by aryl(including heteroaryl), as described herein.

[0105] In the compounds of formula (I), R₅, R₆ and R₇ are independentlyselected from H, alkyl (including branched and unbranched alkyl,substituted and unsubstituted alkyl, cyclic and acyclic alkyl) and aryl(including heteroaryl) or where R₆ and R₇ are in any NR₆R₇ group R₆ andR₇ may be linked to form a heterocyclic group, or where R₅, R₆ and R₇are in a (CONR₅NR₆R₇) group, R₅ and R₆ may be linked to form aheterocyclic group.

[0106] In the compounds of formula (I), R₈ is selected from alkyl(including branched and unbranched alkyl, substituted and unsubstitutedalkyl, cyclic and acyclic alkyl) and aryl (including heteroaryl).

[0107] Where R₅ to R₈ are independently selected from alkyl, preferablyR₅ to R₈ are selected from C₁₋₆ alkyl, preferably C₁₋₆ saturated alkyland more preferably from lower alkyl.

[0108] Where R₆ and R₇, or R₅ and R₆, are linked to form a heterocyclicring said heterocyclic ring may be saturated, partially unsaturated oraromatic, and is preferably saturated. Said heterocyclic ring ispreferably a 5, 6 or 7-membered ring, preferably a 5 or 6-membered ring,and may contain one or more further heteroatom(s) preferably selectedfrom N, O and S.

[0109] In a preferred embodiment, R₁ is NH₂, R₂ is 2-furyl, R₃ is H andR₄ is arylmethyl (including heteroarylmethyl).

[0110] In a particularly preferred embodiment of the invention, thecompounds of formula (I) are selected from:

[0111]4-(2-furyl)-1-(3-methoxybenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine;

[0112]1-(2-fluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine;

[0113]4-(2-furyl)-1-(3-methylbenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine;

[0114]1-(2,6-difluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine;

[0115]4-(2-furyl)-1-(3-phenylpropyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; and

[0116]1-(2-fluorobenzyl)-4-(2-pyridyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine.

[0117] Where chiral the compounds of formula (I) may be in the form of aracemic mixture of pairs of enantiomers or in enantidmerically pureform.

[0118] According to a further aspect of the present invention there isprovided a method of treating or preventing a disorder in which theblocking of purine receptors, particularly adenosine receptors and moreparticularly adenosine A_(2A) receptors, may be beneficial, the methodcomprising administration to a subject in need of such treatment aneffective dose of a compound of formula (I) or a pharmaceuticallyacceptable salt or prodrug thereof.

[0119] The disorder may be caused by the hyperfunctioning of the purinereceptors.

[0120] The present invention may be employed in respect of a human oranimal subject, more preferably a mammal, more preferably a humansubject.

[0121] The disorders of particular interest are those in which theblocling of purine receptors, partiucularly adenosine receptors and moreparticularly adenosine A_(2A) receptors, may be beneficial. These mayinclude movement disorders such as Parkinson's disease, drug-inducedParkinsonism, post-encephalitic Parkinsonism, Parkinsonism induced bypoisoning (for example MPTP, manganese, carbon monoxide) andpost-traumatic Parkinson's disease (punchdrunk syndrome).

[0122] Other movement disorders in which the blocking of purinereceptors, may be of benefit include progressive supernuclear palsy,Huntingtons disease, multiple system atrophy, corticobasal degeneration,Wilsons disease, Hallerrorden-Spatz disease, progressive pallidalatrophy, Dopa-responsive dystonia-Parkinsonism, spasticity or otherdisorders of the basal ganglia which result in abnormal movement orposture. The present invention may also be effective in treatingParkinson's with on-off phenomena; Parkinson's with freezing (end ofdose deterioration); and Parkinson's with prominent dyskinesias.

[0123] The compounds of formula (I) may be used or administered incombination with one or more additional drugs useful in the treatment ofmovement disorders, such as L-DOPA or a dopamine agonist, the componentsbeing in the same formulation or in separate formulations foradministration simultaneously or sequentially.

[0124] Other disorders in which the blocking of purine receptors,particularly adenosine receptors and more particularly adenosine A_(2A)receptors may be beneficial include acute and chronic pain; for exampleneuropathic pain, cancer pain, trigeminal neuralgia, migraine and otherconditions associated with cephalic pain, primary and secondaryhyperalgesia, inflammatory pain, nociceptive pain, tabes dorsalis,phantom limb pain, spinal cord injury pain, central pain, post-herpeticpain and HIV pain; affective disorders including mood disorders such asbipolar disorder, seasonal affective disorder, depression, manicdepression, atypical depression and monodepressive disease; central andperipheral nervous system degenerative disorders including corticobasaldegeneration, demyelinating disease (multiple sclerosis, disseminatedsclerosis), Freidrich's ataxia, motoneurone disease (amyotrophic lateralsclerosis, progressive bulbar atrophy), multiple system atrophy,myelopathy, radiculopathy, peripheral neuropathy (diabetic neuropathy,tabes dorsalis, drug-induced neuropathy, vitamin deficiency), systemiclupus erythamatosis, granulomatous disease, olivo-ponto-cerebellaratrophy, progressive pallidal atrophy, progressive supranuclear palsy,spasticity; schizophrenia and related pyshoses; cognitive disordersincluding dementia, Alzheimers Disease, Frontotemporal dementia,multi-infarct dementia, AIDS dementia, dementia associated withHuntingtons Disease, Lewy body dementia, senile dementia, age-relatedmemory impairment, cognitive impairment associated with dementia,Korsakoff syndrome, dementia pugilans; attention disorders such asattention-deficit hyperactivity disorder (ADHD), attention deficitdisorder, minimal brain dysfunction, brain-injured child syndrome,hyperkinetic reaction childhood, and hyperactive child syndrome; centralnervous system injury including traumatic brain injury, neurosurgery(surgical trauma), neuroprotection for head injury, raised intracranialpressure, cerebral oedema, hydrocephalus, spinal cord injury; cerebralischaemia including transient ischaemic attack, stroke (thromboticstroke, ischaemic stroke, embolic stroke, haemorrhagic stroke, lacunarstroke) subarachnoid haemorrhage, cerebral vasospasm, neuroprotectionfor stroke, peri-natal asphyxia, drowning, cardiac arrest, subduralhaematoma; myocardial ischaemia; muscle ischaemia; sleep disorders suchas hypersomnia and narcolepsy; eye disorders such as retinalischaemia-reperfusion injury and diabetic neuropaathy; cardiovasculardisorders such as claudication and hypotension; and diabetes and itscomplications.

[0125] According to a further aspect of the present invention there isprovided use of a compound of formula (I) or a pharmaceuticallyacceptable salt or prodrug thereof in the manufacture of a medicamentfor the treatment or prevention of movement disorders in a subject.

[0126] According to a further aspect of the invention there is provideda method of treating or preventing movement disorders comprisingadministration to a subject in need of such treatment an effective doseof a compound of formula (I) or a pharmaceutically acceptable salt orprodrug thereof.

[0127] According to a further aspect of the invention there is provideduse of a compound of formula (I) or a pharmaceutically acceptable saltor prodrug thereof in the manufacture of a medicament forneuroprotection in a subject.

[0128] According to a further aspect of the invention there is provideda method of neuroprotection comprising administration to a subject inneed of such treatment an effective dose of a compound of formula (I) ora pharmaceutically acceptable salt or prodrug thereof.

[0129] The medicament for or method of neuroprotection may be of use inthe treatment of subjects who are suffering from or at risk from aneurodegenerative disorder, such as a movement disorder.

[0130] According to a further aspect of the invention, there is providedfor use in therapy a compound of formula (I), or a pharmaceuticallyacceptable salt or prodrug thereof.

[0131] According to a further aspect of the invention, there is provideda compound of formula (I), or a pharmaceutically acceptable salt orprodrug thereof, per se, other than compounds wherein R₂ is selectedfrom pyrazolopyriridines. In a preferred embodiment, there is provided acompound of formula (I), or a pharmaceutically acceptable salt orprodrug thereof, per se, wherein R₂ is selected from 5- or 6-memberedmonocyclic heteroaryl groups.

[0132] According to a further aspect of the invention, there is provideda method of preparing the novel compounds of the present invention.Compounds of formula (I) may be prepared according to conventionalsynthetic methods, such as set out in Reaction Scheme 1.

[0133] Compounds of formula (1) where R₄ is alkyl or substituted alkyl(including arylalkyl, heteroalkylaryl and (CR₉R₁₀)_(n)R₁₁ wherein R₁₁ isCO₂R₅ or CN) may be prepared from compounds of formula (2) by standardmethods such as reaction with an appropriate alkyl halide or substitutedalkyl halide in the presence of a suitable base such as NaH.

[0134] Compounds of formula (1) where R₄ is (CR₉R₁₀)_(n)R₁₁ wherein R₁₁is CONR₆R₇ or CONR₅NR₆R₇ may be prepared from compounds of formula (1)where R₄ is (CR₉R₁₀)_(n)R₁₁ wherein R₁₁ is CO₂R₅ by standard methodssuch as direct reaction with an appropriate amine or hydrazinederivative or by initial hydrolysis of the ester group CO₂R₅ to acarboxylic acid followed by reaction with an appropriate amine orhydrazine derivative in the presence of a standard coupling reagent suchas DCC.

[0135] Compounds of formula (1) where R₄ is (CR₉R₁₀)_(n)R₁₁ wherein R₁₁is C(═NR₅)NR₆R₇ may be prepared from compounds of formula (1) where R₄is (CR₉R₁₀)_(n)R₁₁ wherein R₁₁ is CN by standard methods such astreatment with an appropriate amine in the presence oftrimethylaluminium.

[0136] Compounds of formula (1) where R₄ is CONR₆R₇, wherein one of R₆or R₇ is H, are prepared from compounds of formula (2) by standardmethods such as reaction with an appropriate isocyanate (R₆NCO orR₇NCO). Compounds of formula (1) where R₄ is CONR₆R₇, wherein R₆ and R₇are alkyl or aryl or are linked to form a heterocyclic group, areprepared from compounds of formula (2) by standard methods such asreaction with an appropriate carbamoyl chloride (R₆R₇NCOCl) in thepresence of a suitable base such as Et₃N.

[0137] Compounds of formula (1) wherein R₄ is CONR₅NR₆R₇ are preparedfrom compounds of formula (2) by standard methods such as reaction withan appropriate carbamoyl chloride R₆R₇NR₅NCOCl in the presence of asuitable base such as Et₃N.

[0138] Compounds of formula (1) where R₄ is COR₆ or SO₂R₈ are preparedfrom compounds of formula (2) by standard methods such as reaction withan appropriate acid chloride (ClCOR₆) or sulphonyl chloride (ClSO₂R₈) inthe presence of a suitable base such as Et₃N.

[0139] Compounds of formula (1) where R₄ is CO₂R₈ are prepared fromcompounds of formula (2) by standard methods such as reaction with anappropriate chloroformate (ClCO₂R₈) or dicarbonate (O(CO₂R₈)₂) in thepresence of a suitable base, if required, such as Et₃N and in thepresence of a suitable catalyst, if required, such as DMAP.

[0140] Alternatively compounds of formula (1) are prepared fromcompounds of formula (3) by standard methods such as aryl couplingreactions. Suitable aryl coupling reactions would include reaction of acompound of formula (3) with a heteroaryl trialkylstannane, aheteroarylboronic acid or boronic ester, or a heteroaryl zinc halidereagent in the presence of a suitable catalyst such as a palladiumcatalyst. Suitable heteroaryl trialkylstannane, heteroarylboronic acidor boronic ester, or heteroaryl zinc halide reagents are eithercommercially available, known in the literature or may be synthesised bystandard methods analogous to those described in the literature. Incertain cases it may be advantageous to use a protecting group toprotect vulnerable functionality which may be present in the heteroarylcoupling partner. This would be particularly appropriate where theheteroaryl group R₂ is imidazolyl, pyrazolyl or triazolyl whereprotection of an unsubstituted ring nitrogen may be necessary tofacilitate the coupling reaction. Suitable protecting groups in suchcases would include trimethylsilylethoxymethyl which can be introducedand removed at a convenient point in the synthesis by standard methods.

[0141] Compounds of formula (2) are prepared from compounds of formula(4) by standard methods such as aryl coupling reactions as describedabove. Compounds of formula (4) where R₁ is alkyl, aryl, alkylthio,halogen and NR₆R₇ are either known in the literature or are prepared bymethods analogous to those described in the literature.

[0142] Compounds of formula (3) are prepared from compounds of formula(4) by standard methods such as those described above. Compounds offormula (3) where R₁ is alkyl, aryl, alkylthio, halogen or NR₆R₇ areeither known in the literature or may be prepared by methods analogousto those described in the literature.

[0143] Compounds of formula (1) may alternatively be prepared bystandard synthetic methods such as those illustrated in Reaction Scheme2.

[0144] Compounds of formula (1) where R₁ is NR₆R₇, alkoxy, aryloxy,alkylthio, arylthio or CN are prepared from compounds of formula (5) bystandard methods such as treatment with an appropriate nucleophile suchas an amine (HNR₆R₇), alcohol, thiol or cyanide in the presence of asuitable base if required.

[0145] Compounds of formula (5) are prepared from compounds of formula(6) by standard methods such as aryl coupling reactions as describedabove.

[0146] Compounds of formula (6) are either known in the literature orare prepared by methods analogous to those described in the literature.For example compounds of formula (6) are prepared from compounds offormula (7) by standard methods such as treatment with a chlorinatingreagent such as POCl₃.

[0147] Compounds of formula (7) are either known in the literature orare prepared by methods analogous to those described in the literature.For example compounds of formula (7) are prepared from compounds offormula (8) by standard methods such as heating in the presence of urea.Compounds of formula (8) are either known in the literature or areprepared by methods analogous to those described in the literature.

[0148] Compounds of formula (1) where R₁ is NR₅COR₆, NR₅CO₂R₈ orNR₅SO₂R₈ wherein R₅ is H, alkyl or aryl, are prepared from compounds offormula (1) where R₁ is NR₆R₇, wherein one of R₆ or R₇ is H and theother is alkyl or aryl, by standard methods such as reaction with anappropriate acid chloride (ClCOR₆), chloroformate (ClCO₂R₈) or sulphonylchloride (ClSO₂R₈).

[0149] Compounds of formula (1) where R₁ is NR₅CONR₆R₇ wherein R₅ is H,alkyl or aryl, are prepared from compounds of formula (1) where R₁ isNR₆R₇, wherein one of R₆ or R₇ is H and the other is alkyl or aryl, bystandard methods such as reaction with an appropriate isocyanate (R₆NCOor R₇NCO) or an appropriate carbamoyl chloride (R₆R₇NCOCl).

[0150] Compounds of formula (1) where R₃ is H, alkyl, halogen, OR₅, SR₅or NR₆R₇ may be prepared by the methods described above. Suitableintermediates such as compounds of formula (3) and (4) where R₃ is asdescribed above, are either known in the literature or are prepared bymethods which are analogous to those described in the literature.

[0151] In the compounds of the present invention, where any of thegroups R₁ to R₈ is an alkyl group or aryl group or where any of thegroups R₁ to R₈ contains an alkyl or aryl substituent, the alkyl or arylgroup may also be substituted. It will be appreciated by those skilledin the art that certain substituents on the alkyl or aryl groupsmentioned above may be introduced directly as an integral part of thesubstituent R₁ to R₈ by using the synthetic methods described above. Inother cases it may be advantageous to introduce certain substituents onthe alkyl or aryl groups mentioned above by chemical transformation ofother substituent groups. For example where the alkyl or aryl groupmentioned above contains an amino substituent this may be converted bystandard methods to an alkylamino or dialkylamino group by standardmethods such as alkylation or reductive alkylation, or to an amide,carbamate, urea or sulphonamide by standard methods such as thosedescribed above. Additionally, for example, where the alkyl or arylgroup mentioned above contains a carboxylic ester substituent this maybe converted to an amide or hydrazide derivative by standard methodssuch as reaction with an amine or hydrazine directly or in the presenceof a catalyst such as Me₃Al if required. It will be appreciated by thoseskilled in the art that substituents such as an amino group or acarboxylic ester group may also be transformed by standard methods to awide range of additional substituent groups.

[0152] According to a further aspect of the invention, there is provideda pharmaceutical composition comprising a compound of formula (I) incombination with a pharmaceutically acceptable carrier or excipient anda method of making such a composition comprising combining a compound offormula (I) with a pharmaceutically acceptable carrier or excipient.

[0153] The pharmaceutical compositions employed in the present inventioncomprise a compound of formula (I), or pharmaceutically acceptable saltsor prodrugs thereof, and may also contain a pharmaceutically acceptablecarrier and optionally other therapeutic ingredients known to thoseskilled in the art. The term, “pharmaceutically acceptable salts”,refers to salts prepared from pharmaceutically acceptable non-toxicacids including inorganic acids and organic acids.

[0154] Where the compounds of formula (I) are basic, salts may beprepared from pharmaceutically acceptable non-toxic acids includinginorganic and organic acids. Such acids include acetic, benzenesulfonic,benzoic, camphorsulfonic, citric, ethenesulfonic, fumaric, gluconic,glutamic, hippuric, hydrobromic, hydrochloric, isethionic, lactic,maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic,pantothenic, phosphoric, succinic, sulfuric, tartaric, oxalic,p-toluenesulfonic and the like. Particularly preferred are hydrochloric,hydrobromic, phosphoric, and sulfuric acids, and most particularlypreferred is the hydrochloride salt.

[0155] Any suitable route of administration may be employed forproviding the patient with an effective dosage of a compound of formula(I). For example, oral, rectal, parenteral (intravenous, intramuscular),transdermal, subcutaneous, and the like may be employed. Dosage formsinclude tablets, troches, dispersions, suspensions, solutions, capsules,patches, and the like. The most suitable route in any given case willdepend on the severity of the condition being treated. The mostpreferred route of administration of the present invention is the oralroute. The compositions may be conveniently presented in unit dosageform and prepared by any of the methods well known in the art ofpharmacy.

[0156] In practical use, the compounds of formula (I) can be combined asthe active ingredient in intimate admixture with a pharmaceuticalcarrier according to conventional pharmaceutical compounding techniques.The carrier may take a wide variety of forms depending on the form ofpreparation desired for administration, e.g. oral or parenteral (e.g.intravenous). In preparing the compositions for oral dosage form, any ofthe usual pharmaceutical media may be employed as carriers, such as, forexample, water, glycols, oils, alcohols, flavouring agents,preservatives, colouring agents, and the like in the case of oral liquidpreparations (such as suspensions, solutions and elixirs) or aerosols;or carriers such as starches, sugars, micro-crystalline cellulose,diluents, granulating agents, lubricants, binders, disintegratingagents, and the like may be used in the case of oral solid preparationssuch as, for example, powders, capsules, and tablets, with the solidoral preparations being preferred over the liquid preparations. The mostpreferred solid oral preparation is tablets.

[0157] Because of their ease of administration, tablets and capsulesrepresent the most advantageous oral dosage unit form in which casesolid pharmaceutical carriers are employed. If desired, tablets may becoated by standard aqueous or non-aqueous techniques.

[0158] In addition to the common dosage forms set out above, thecompounds of formula (I) may also be administered by controlled releasemeans and/or delivery devices such as those described in U.S. Pat. Nos.:3,845,770; 3,916,899; 3,536,809; 3,598,123; 3,630,200; 4,008,719;4,687,660; and 4,769,027, the disclosures of which are herebyincorporated by reference.

[0159] Pharmaceutical compositions employed in the present inventionsuitable for oral administration may be presented as discrete units suchas capsules, cachets, or tablets, or aerosol sprays each containing apredetermined amount of the active ingredient as a powder or granules, asolution or a suspension in an aqueous liquid, an oil-in-water emulsion,or a water-in-oil liquid emulsion. Such compositions may be prepared byany of the methods of pharmacy, but all methods include the step ofbringing the active ingredient into association with the carrier whichconstitutes one or more necessary ingredients. In general, thecompositions are prepared by uniformly and intimately admixing theactive ingredient with liquid carriers or finely divided solid carriersor both, and then, if necessary, shaping the product into the desiredpresentation.

[0160] For example, a tablet may be prepared by compression or moulding,optionally with one or more accessory ingredients. Compressed tabletsmay be prepared by compressing in a suitable machine the activeingredient in a free-flowing form such as powder or granules, optionallymixed with a binder, a lubricant, an inert diluent, and/or a surfaceactive or dispersing agent. Moulded tablets may be made by moulding in asuitable machine a mixture of the powdered compound moistened with aninert liquid diluent.

[0161] The invention is further defined by reference to the followingexamples. It will be apparent to those skilled in the art that manymodifications, both to materials and methods, may be practised withoutdeparting from the purpose and interest of this invention.

EXAMPLES Synthetic Examples

[0162] The invention is illustrated with reference to the followingExamples, as set out in Table 1. The synthesis of these compounds isperformed using the general Synthetic Methods A to Q describedhereinafter. The Synthetic Method used for the preparation of eachExample is given in parentheses in column 1 of Table 1. Analytical dataare given in Table 2. TABLE 1 Example Structure Compound Name 1 (B)

6-chloro-4-(2-furyl)-1-(2-phenylethyl)-1H- pyrazolo[3,4-d]pyrimidine 2(N)

4-(2-furyl)-N,N-dimethyl-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 3 (O)

1H-4-(2-furyl)-N-(2-hydroxyethyl)-1-(2-phenylethyl)-pyrazolo[3,4-d]pyrimidine-6-amine 4 (B)

tert-butyl 6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-carboxylate 5 (C)

4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 6 (P)

6-amino-N-benzyl-4-(2-furyl-1H-pyrazolo[3,4- d]pyrimidine-1-carboxamide7 (D)

1-benzyl-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine- 6-amine 8 (D)

1-(3-chlorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 9(D)

4-(2-furyl)-1-(4-nitrobenzyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 10(D)

1-(3-cyanobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 11(D)

1-(2-chlorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 12(D)

4-(2-furyl)-1-(3-methoxybenzyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 13(D)

4-(2-furyl)-1,N,N-tris(3-methoxybenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 14 (D)

1-(2-fluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 15(D)

4-(2-furyl)-1-(3-methylbenzyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 16(D)

methyl 3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylmethyl)benzoate 17 (D)

4-(2-furyl)-1-(4-sulphonylbenzyl)-1H-pyrazolo[3,4- d]pyrimdine-6-amine18 (D)

4-(2-furyl)-1-(2-phenylethyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 19(D)

1-cyclohexylmethyl-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 20(G)

3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidin-1-ylmethyl)benzoicacid 21 (D)

4-(2-furyl)-1-(1-methylethyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 22(D)

4-(2-furyl)-1-(4-trifluoromethylbenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 23 (D)

4-(2-furyl)-1-n-pentyl-1H-pyrazolo[3,4- d]pyrimidine-6-amine 24 (D)

1-(2,6-difluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3.4- d]pyrimidine-6-amine25 (D)

4-(2-furyl)-1-(3-pyridylmethyl)-1H-pylazolo[3,4- d]pyrimidine-6-amine 26(D)

ethyl 6-amino-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidin-1-ylacetate 27(G)

6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1- ylacetic acid 28 (I)

1-(2-fluorobenzyl)-4-(2-thienyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine29 (H)

6-amino-4-(2-furyl)-N-(2-pyridyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 30 (D)

4-(2-fury1)-1-(3-nitrobenzyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 31(D)

4-(2-furyl)-1-(3-phenylpropyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 32(E)

1-(3-aminobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 33(J)

1-(2-fluorobenzyl)-4-(2-pyridyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine34 (H)

6-amino-N-benzyl-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidin-1-ylacetamide35 (H)

6-amino-4-(2-furyl)-N-phenyl-1H-pyrazolo[3,4- d]pyrimidin-1-ylacetamide36 (H)

6-amino-N-(3-chlorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 37 (H)

6-amino-4-(2-furyl)-N-(2-furylmethyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 38 (J)

1-(2-fluorobenzyl)-4-(2-thiazolyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine39 (D)

4-(2-furyl)-1-(2-furylmethyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 40(F)

4-(2-furyl)-1-(4-methylphenylsulphonyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 41 (J)

1-(2-fluorobenzyl)-4-(1-methyl-2-imidazolyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 42 (K)

1-(2-fluorobenzyl)-4-(2-imidazolyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 43 (H)

6-amino-4-(2-furyl)-N-(3-methoxyphenyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 44 (H)

6-amino-4-(2-furyl)-N-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 45 (H)

6-amino-N-(2-fluorophenyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 46 (D)

3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylmethyl)-N-methylbenzamide 47 (D)

3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylmethyl)-N,N-dimethylbenzamide 48 (H)

6-amino-4-(2-furyl)-N-(2-methoxybenzyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 49 (H)

6-amino-N-(2-fluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide 50 (K)

1-(4-methylbenzyl)-4-(1H-pyrazol-3-yl)-1H-pyrazolo[3,4-d]pyrimidne-6-amine 51 (K)

1-(2-fluorobenzyl)-4-(1,2,4-triazol-3-yl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 52 (D)

4-(2-furyl)-1-(2-nitrobenzyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 53(F)

N-(4-(2-furyl)-1-(3-(2- thiophenesulphonamido))benzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-yl)-2-thiophenesulphonamide 54 (F)

N-((3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-ylmethyl)phenyl-2- thiophenesulphonamide 55 (K)

1-(2-fluorobenzyl)-4-(3-pyrazolyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine56 (E)

1-(2-aminobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 57(F)

N-((3-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-ylmethyl)phenyl-1-methyl-1H- imidazol-4-sulphonamide 58(K)

1-(3-nitrobenzyl)-4-(1,2,4-triazol-3-yl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 59 (K)

1-(3-nitrobenzyl)-4-(3-pyrazolyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine60 (E)

1-(3-aminobenzyl)-4-(1,2,4-triazol-3-yl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 61 (J)

1-(3-nitrobenzyl)-4-(2-thiazolyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine62 (E)

1-(3-aminobenzyl)-4-(2-thiazolyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine63 (E)

1-(3-aminobenzyl)-4-(1H-pyrazol-3-yl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine 64 (K)

1-(3-methoxybenzyl)-4-(1H-pyrazol-3-yl)-1H-pyrazolo[3,4-d]pyrimdine-6-amine 65 (Q)

4-(2-furyl)-1-(4-indolylmethyl)-1H-pyrazolo[3,4- d]pyrimidine-6-amine 66(D)

tert-butyl 4-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-ylmethyl)indole-1-carboxylate

[0163] Synthetic Methods

[0164] Method A

[0165] tert-Butyl6-amino-4-chloro-1H-pyrazolo[3,4-d]pyrimidine-1-carboxylate

[0166] A solution of 2-amino-4-chloro-1H-pyrazolo[3,4d]pyrimidine (848mg, 5 mmol) in DMF (5 mL) was treated with Et₃N (834 μL, 6 mmol),di-t-butyl dicarbonate (1.31 g, 6 mmol) and a catalytic amount of DMAP,stirred at room temperature for 1 h, poured into water, extracted withEtOAc, dried (MgSO₄), concentrated in vacuo and purified bychromatography (EtOAc:Heptane, 1:1) to give the title compound (312 mg,23%) as a cream solid.

[0167] Method B

[0168] tert-Butyl6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-carboxylate (Example4)

[0169] A solution of tert-butyl6-amino-4-chloro-1H-pyrazolo[3,4-d]pyrimidine-1-carboxylate (269 mg, 1mmol) in DMF (2 mL) was treated with PdCl₂(PPh₃)₂ (35 mg, 0.05 mmol) and2-(tributylstannyl)furan (315 μL, 1 mmol), stirred at room temperaturefor 16 h and the resulting solid filtered and washed with EtOAc to givethe title compound (298 mg, 99%) as a cream solid.

[0170] Method C

[0171] 4-(2-Furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine (Example 5)

[0172] A solution of tert-butyl6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-carboxylate (204 mg,0.68 mmol) in MeOH (2 mL) was treated with dimethylamine in water (0.5mL, 40%), refluxed for 1 h, cooled and the resulting solid filtered andwashed with water to give the title compound (95 mg, 70%) as a creamsolid.

[0173] Method D

[0174]1-(2-Fluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 14)

[0175] A solution of 4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(219 mg, 1 mmol) in DMF (2 mL) at 0° C. was treated with NaH (40 mg,60%, 1 mmol), stirred for 20 min, treated with 2-fluorobenzyl bromide(120 μL, 1 mmol), stirred at room temperature for 1 h, quenched withwater, extracted with EtOAc, dried (MgSO₄), concentrated in vacuo andpurified by chromatography EtOAc:Heptane, 1:4) to give the titlecompound (250 mg, 76%) as a cream solid.

[0176]4-(2-Furyl)-1-(3-nitrobenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 30)

[0177] A solution of 4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(603 mg, 3 mmol) in DMF (3 mL) at 0° C. was treated with NaH (120 mg,60%, 3 mmol), stirred for 20 min, treated with 3-nitrobenzyl bromide(648 mg, 3 mmol), stirred at room temperature for 1 h, poured intowater, extracted with EtOAc, dried (MgSO₄) and concentrated in vacuo.The crude product was purified by chromatography EtOAc:Heptane, 1:1) togive the title compound as a cream solid (472 mg, 47%). A portion of thesolid (70 mg) was suspended in MeOH, treated with HCl in dioxan (4-M, 1mL), diluted with diethyl ether and filtered to give the hydrochloridesalt of the title compound (79 mg, 100%) as a yellow solid.

[0178] 4-Chloro-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine

[0179] This was prepared from4-chloro-1H-pyrazolo[3,4-d]pyrimidine-6-amine by Method D to give thetitle compound (562 mg, 34%) as a cream solid: mp 197-198° C.; NMR δ_(H)(400 MHz, CDCl₃) 5.23 (1H, br s), 5.51 (2H, s), 7.03-7.16 (3H, m),7.23-7.31 (1H, m) and 7.91 (1H, s); IR ν_(max) (Nujol)/cm⁻¹ 3489, 3288,3169, 2923, 1631, 1454, 1378, 1223 and 760; Retention time: 2.60 min.

[0180] 4-Chloro-1-(3-methoxybenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine

[0181] This was prepared from4-chloro-1H-pyrazolo[3,4-d]pyrimidine-6-amine by Method D to give thetitle compound: IR ν_(max) (DR)/cm⁻¹ 3435, 3321, 3217, 2923, 1603, 1456,1378, 1254, 1155, 1034, 980 and 788; NMR δ_(H) (400 MHz, DMSO) 8.03 (1H,s), 7.32 (2H, br s), 7.22 (1H, t, J 7.5 Hz), 6.84 (1H, dd, J 9.0, 3.5Hz), 6.79-6.75 (1H, m), 6.71 (1H, d, J 8.5 Hz), 5.36 (2H, s) and 3.71(3H, s).

[0182] Method E

[0183]1-(3-Aminobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 32)

[0184] A suspension of4-(2-furyl)-1-(3-nitrobenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine (396mg, 1.18 mmol) in EtOH (5 mL) was heated to 50° C., treated with asolution of SnCl₂.2H₂O (798 mg, 3.54 mmol) in conc. HCl (1.8 mL),stirred at 50° C. for 2 h then heated at 70° C. for 2 h. The reactionmixture was cooled, basified (5-M NaOH) filtered and the resulting solidsuspended in MeOH, treated with HCl in dioxan (4-M, 2 mL), diluted withdiethyl ether and filtered to give the title compound (419 mg, 94%) as ayellow solid.

[0185] Method F

[0186]N-((3-(6-Amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-ylmethyl)phenyl-2-thiophenesulphonamide(Example 54)

[0187] A solution of1-(3-aminobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine6-amine (153mg, 0.5 mmol) in pyridine (2 mL) was treated with 2-thiophenesulphonylchloride (91 mg, 0.5 mmol), stirred at room temperature for 16 h, pouredinto water, extracted with EtOAc, dried (MgSO₄), concentrated in vacuoand purified by chromatography (MeOH:DCM, 1:99) to give the titlecompound (49 mg, 22%) as a cream solid.

[0188] Method G

[0189] 6-Amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetic acid(Example 27)

[0190] A solution of ethyl6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetate (350 mg,1.22 mmol) in MeOH (2 mL) was treated with NaOH (1-M, 1 mL, 1 mmol),refluxed for 15 min, cooled, acidified and filtered to give the titlecompound (300 mg, 95%) as a white solid.

[0191] Method H

[0192]6-Amino-4-(2-furyl)-N-(2-pyridyl)-1H-pyrazolo[3,4-d]pyrimidin-1-ylacetamide(Example 29)

[0193] A solution of6-amino-4-(2-furyl)-1H-pyrazolo[3,4d]pyrimidin-1-ylacetic acid (200 mg,0.77 mmol) in DMF (3 mL) was treated with carbonyl diimidazole (125 mg,0.77 mmol), stirred at room temperature for 2 h, treated with2-aminopyridine (72 mg, 0.77 mmol), heated to 50° C. for 3 h, cooled anddiluted with water. The resulting white solid was filtered, suspended inMeOH, treated with HCl in dioxan (4-M, 1 mL) diluted with diethyl etherand filtered to give the title compound (187 mg, 59%) as a yellow solid.

[0194] Method I

[0195]1-(2-Fluorobenzyl)-4-(2-thienyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 28)

[0196] A stirred solution of4-chloro-1-(2-fluorobenzyl)-1H-pyrazolo[3,4d]pyrimidine-6-amine(139 mg,0.5 mmol) in dry TBF (10 mL) was treated with 2-thiopheneboronic acid(128 mg, 1.0 mmol), Pd(PPh₃)₄ (50 mg, 10 mol %) and saturated aqueousNaHCO₃ solution (2 mL), refluxed for 30 min, diluted with H₂O, extractedwith EtOAc, dried MgSO₄) and concentrated in vacuo. The resulting darkbrown oil was purified by chromatography [SiO₂; heptane:EtOAc (1:1) then(1:3)] to give the title compound (32 mg, 20%) as a cream solid.

[0197] Method J

[0198]1-(2-Fluorobenzyl)-4-(2-thiazolyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 38)

[0199] A stired solution of thiazole (0.14 mL, 2 mmol) in dry TBF (10mL) at −78° C., under argon was treated n-BuLi (1.6-M in hexanes, 1.25mL, 2 mmol), stirred for 15 min, treated with ZnCl₂ solution (1-M inEt₂O, 2 mL, 2 mmol) then allowed to warm gradually to room temperature.The mixture was treated with4-chloro-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine (278mg, 1 mmol) and Pd(PPh₃)₄ (100 mg, 10 mol %), refluxed for 2 h, dilutedwith saturated NH₄Cl solution, extracted with EtOAc, dried (MgSO₄) andconcentrated in vacuo. The resulting brown oil was purified bychromatography [SiO₂; heptane:EtOAc (4:1) then (3:1)] to give the titlecompund (101 mg, 31%) as a cream solid.

[0200] Method K

[0201]1-(2-Fluorobenzyl)-4-(3-pyrazolyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 55)

[0202] A stirred solution of 1-(2-trimethylsilylethyl)pyrazole (615 mg,3.1 mmol) in dry THF (10 mL) at −78° C., under argon was treated withn-BuLi (1.6-M in hexanes, 1.9 mL, 3.1 mmol), stirred for 20 min, treatedwith ZnCl₂ solution (1-M in Et₂O, 3.1 mL, 3.1 mmol) and allowed to warmgradually to room temperature. The mixture was treated with4-chloro-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-d]pynmidine-6-amine (430 mg,1.55 mmol) and Pd(PPh₃)₄ (170 mg, 10 mol %), refluxed for 1 h, dilutedwith saturated NH₄Cl solution, extracted with EtOAc, dried (MgSO₄) andconcentrated in vacuo. The resulting brown oil was purified bychromatography [SiO₂; heptane-EtOAc (3:1)] to give the coupled productas a cream solid. This material was dissolved in MeOH (10 mL), treatedwith anhydrous HCl (4-M in dioxan, 5 mL), stirred for 17 h, concentratedin vacuo, diluted with Et₂O and filtered to give the title compound (216mg, 40%) as a cream solid.

[0203] Method L

[0204] 5-Amino-1-(2-phenylethyl)-1H-pyrazole-4-carboxylic acid

[0205] A mixture of conc. H₂SO₄ (15 mL) and water (15 mL) was treatedwith 5-amino-1-(2-phenylethyl)-1H-pyrazole-4-carbonitrile (5.0 g, 23.6mmol), heated at 60° C. for 1 h, poured into water, extracted withEtOAc, dried (MgSO₄), concentrated in vacuo, and recrystallised(EtOAc/MeOH) to give the title compound (2.53 g, 47%) as a cream solid.

[0206] Method M

[0207] 6-Hydroxy-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidin-4-ol

[0208] A mixture of 5-amino-1-(2-phenylethyl)-1H-pyrazole4-carboxylicacid (1.87 g, 8.1 mmol) and urea (1.46 g, 24 mmol) was heated at 180° C.for 5 h, cooled and the resulting solid suspended in boiling water,filtered and washed with water to give the impure title compound (2.18g, 105%,) as a cream solid.

[0209] Method N

[0210] 4,6-Dichloro-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidine

[0211] A solution of6-hydroxy-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidin-4-ol (2.13 g,8.32 mmol) in PhPOCl₂ (8 mL) was heated to 165° C. for 16 h, cooled,poured onto ice and the solid isolated by filtration. The solid wassuspended in DCM, filtered through a silica pad and the filtrate wasconcentrated in vacuo to give the title compound (556 mg, 23%) as acolourless oil.

[0212] Method O

[0213]4-(2-Furyl)-N-(2-hydroxyethyl)-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(Example 3)

[0214] A solution of6-chloro-4-(2-furyl)-1-(2-phenylethyl)-1H-pyrazolo[3,4-d]pyrimidine (162mg, 0.5 mmol) in NMP (1 mL) was treated with ethanolamine (60 μL, 1mmol), heated at 100° C. for 16 h, cooled and purified by chromatography(EtOAc:Heptane, 2:1). The resulting colourless oil was crystallised(MeOH/water) and filtered to give the title compound (100 mg, 57%) as awhite solid.

[0215] Method P

[0216]6-Amino-N-benzyl-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-carboxamide(Example 6)

[0217] A solution of 4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine(210 mg, 1 mmol) in DMF (2 mL) was treated with benzyl isocyanate (123μL, 1 mmol) and a catalytic amount of DMAP, stirred at room temperaturefor 1 h, poured into water, extracted with EtOAc, dried (MgSO₄),concentrated in vacuo and purified by preparative HPLC (MeOH/H₂Ogradient) to give the title compound (80 mg, 24%) as a pale yellowsolid.

[0218] Method Q

[0219]4-(2-Furyl)-1-(4-indolymethyl)-1H-pyrazolo[3,4-d]pyrimidine-6amine(Example 65)

[0220] A solution of tert-butyl4-(6-amino-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-1-ylmethyl)indole-1-carboxylate(92 mg, 0.17 mmol) in MeOH (3 mL) was treated with NaOMe (45 mg, 0.84mmol), refluxed for 2 h, cooled, diluted with water (15 mL) and filteredto give the title compound (45 mg, 82%) as an off white powder.

[0221] Table 2—Analytical Data

[0222] HPLC is carried out using the following conditions: Column.Supelcosil ABZ⁺ (170×4.6 mm), particle size 5 μM, mobile phase MeOH: 10mM aq NH₄OAc (80:50), flow rate 1.0 mL/min., detection wavelength λ=230nM. Retention times are provided in Table 2. Example Yield(%) PhysicalData 1 96 Mp85.1-85.6° C.; IRν_(max) Nujol)/cm⁻¹ 2925, 2854, 1604, 1562,1465, 1377, 1334, 1148, 1014 and 926; NMR(CDCl₃)8.48(1H, s), 7.80(1H, d,J1.2Hz), 7.60(1H, d, J3.6Hz), 7.27-7.17(5H, m), 6.69(1H, dd, J 3.6,2.0Hz), 4.69(2H, m) and 3.26(2H, t, J8.0Hz); Anal. Calcd forC₁₇H₁₃ClN₄O: C, 67.89; H, 4.00; N, 17.24. Found: C, 62.70; H, 4.06; N,16.99. 2 67 Mp90.9-91.1° C.; IRν_(max) Nujol)/cm⁻¹ 2926, 2855, 1609,1584, 1549, 1488, 1456, 1401, 1160, and 1010; NMR(CDCl₃)8.21(1H, s),7.71(1H, d, J1.0Hz), 7.36(1H, d, J3.3Hz), 7.28-7.17(5H, m), 6.61(1H, dd,J 3.4, 1.8Hz), 4.53(2H, m), 3.28(6H, s) and 3.23(2H, t, J7.8Hz); Anal.Calcd for C₁₉H₁₉N₅O: C, 68.45; H, 5.74; N, 21.00. Found: C, 68.40; H,5.77; N, 20.90. 3 57 Mp118.6-119.3° C.; IRν_(max) Nujol)/cm⁻¹ 3317,3099, 1613, 1568, 1543 and 1481; NMR δH(400MHz, CDCl₃)3.21(2H, t,J7.5Hz), 3.60-3.68 (2H, m), 3.83-3.89(2H, m), 4.51(2H, t, J7.5Hz),5.61(1H, s), 6.59-6.63 (1H, m), 7.15-7.28(5H, m), 7.32-7.37(1H, m),7.69-7.74(1H, m)and 8.22(1H, s); Anal. Calcd for C₁₉H₁₉N₅O₂: C, 65.32;H, 5.48; N, 20.03. Found: C, 65.24; H, 5.48; N, 19.91. 4 99Mp261.9-262.7° C.; NMR δ_(H) 400MHz, DMSO)1.61(9H, s), 6.79-6.82 (1H,m), 7.18(2H, s), 7.44(1H, d, J3.0Hz), 8.08(1H, s), 8.42(1H, s); Anal.Calcd for C₁₄H₁₅N₅O₃ · 0.4 H₂O: C, 54.50; H, 5.16; N, 22.70. Found: C,54.84; H, 5.18; N, 22.35. 5 70 Mp237.5-238.2° C.; IRν_(max) Nujol)/cm⁻¹3498, 3341, 3210, 3134, 2924, 2854, 1663, 1639, 1596, 1561, 1463 and1377; NMR δ_(H) 400MHz, DMSO)6.70(2H, s), 6.76-6.78(1H, m), 7.40(1H, d,J3.5Hz), 8.04(1H, s), 8.21(1H, s)and 12.99(1H, s). 6 24 Mp171.2-171.6°C.; IRν_(max) Nujol)/cm⁻¹ 3461, 3307, 3200, 3063, 3029, 1643, 1613,1576, 1557, 1479 and 1379; NMR δ_(H) 400MHz, DMSO)4.56(2H, d, J6.0Hz),6.81-6.83(1H, m), 7.23-7.30(1H, m), 7.30-7.41(5H, m), 7.49(1H, d,J3.5Hz), 8.10(1H, s), 8.47(1H, s)and 9.30(1H, t, J6.2Hz); Anal. Calcdfor C₁₇H₁₄N₆O₂ · 0.5 H₂O: C, 59.47; H, 4.40; N, 24.48. Found: C, 59.75;H, 4.22; N, 24.45. 7 Mp189.6-189.8° C.; IRν_(max) Nujol)/cm⁻¹ 3324,3195, 2955, 2854, 1655, 1580, 1563, 1514, 1483, 1446 and 1432; NMR δ_(H)400MHz, DMSO) 8.27(1H, s), 8.06(1H, d, J1.2Hz), 7.44(1H, d, J3.6Hz),7.33-7.18 (3H, m), 6.91(2H, br s), 6.79(1H, dd, J3.2, 1.6Hz)and 5.43(2H,s); Anal Calcd for C₁₆H₁₀N₅O · 0.4 H₂O: C, 64.38; H, 4.66; N, 23.46.Found: C, 64.58; H, 4.51; N, 23.18. 8 37 Mp187.7-187.8° C.; IRν_(max)Nujol)/cm⁻¹ 3363, 3323, 3201, 2924, 2854, 1645, 1610, 1580, 1557, 1514,1483 and 1445; NMR δ_(H) 400MHz, DMSO)8.30(1H, s), 8.06(1H, d, J0.8Hz),7.45(1H, d, J3.2Hz), 7.38-7.13(3H, m), 6.94(2H, br s), 6.79(1H, dd,J3.2, 1.6Hz)and 5.44(2H, s); Anal. Calcd for C₁₆H₁₂ClN₅O · 0.1 H₂O: C,58.67; H, 3.75; N, 21.38. Found: C, 58.97; H, 3.86; N, 20.95. 9Mp240.3-240.8° C.; IRν_(max) Nujol)/cm⁻¹ 3325, 3204, 2922, 2854, 1652,1605, 1580, 1555, 1523, 1467, 1377 and 1344; NMR δ_(H) 400MHz,DMSO)8.28(1H, s), 8.16(2H, d, J8.8Hz), 8.01(1H, s), 7.45-7.42 (3H, m),6.76(1H, m), 6.70(2H, br s), and 5.57(2H, s); Anal. Calcd for C₁₆H₁₂N₆O₃· 0.7 H₂O: C, 49.87; H, 3.77; N, 21.81. Found: C, 50.09; H, 3.46; N,21.59. 10 Mp226.8-226.9° C.; NMR δ_(H) 400MHz, DMSO)8.31(1H, s), 8.06(1H, d, J1.2Hz), 7.75(1H, d, J7.6Hz), 7.67(1H, s), 7.57-7.45(3H, m),6.95(2H, br s), 6.79(1H, dd, J3.6, 1.6Hz)and 5.50(2H, s); Anal. Calcdfor C₁₇H₁₂N₆O · 0.75 H₂O: C, 61.91; H, 4.13; N, 25.48. Found: C, 62.14;H, 3.81; N, 25.37. 11 Mp159.4-162.2° C.; NMR δ_(H) 400MHz, DMSO)8.32(1H,s), 8.07 (1H, s), 7.49(1H, d, J8.0Hz), 7.46(1H, d, J3.4Hz),7.34-7.24(2H, m), 6.94(2H, br s), 6.80(1H, dd, J3.6, 1.9Hz)and 5.50(2H,s). 12 Mp191.7-191.8° C.; NMR δ_(H) 400MHz, DMSO)8.28(1H, s), 8.05 (1H,d, J0.8Hz), 7.44(1H, d, J3.6Hz), 7.22(1H, t, J8.0Hz), 6.91(2H, s),6.85-6.72(5H, m), 5.93(2H, s)and 3.70(3H, s). Anal. Calcd. forC₁₇H₁₅N₅O₂ · 0.2 H₂O: C, 62.84; H, 4.78; N, 21.55. Found: C, 62.91; H,4.71; N, 21.22. 13 IRν_(max) Nujol)/cm⁻¹ 2923, 2854, 1616, 1588, 1552,1531, 1487, 1456, 1377, 1245 and 1042; NMR δ_(H) 400MHz, DMSO)8.30(1H,s), 8.07 (1H, s), 7.45(1H, d, J3.6Hz), 7.20-7.11(3H, m), 6.92-6.71(10H,m), 5.38(2H, s), 4.98-4.89(4H, m)and 3.66(9H, s); Anal. Calcd forC₃₃H₂₁N₅O₄ · H₂O: C, 68.38; H, 5.74; N, 12.08; Found: C, 68.74; H, 5.47;N, 12.10; M/Z 562(M + H)⁺. 14 28 Mp210.3-210.4° C.; IRν_(max)Nujol)/cm⁻¹ 3339, 3203, 3061, 1655, 1582, 1561, 1407, 1454, 1228 and758; NMR δ_(H) 400MHz, DMSO) 5.47(2H, s), 6.77-6.80(1H, m), 6.93(2H, s),7.04-7.09(1H, m), 7.10-7.16 (1H, m), 7.19-7.26(1H, m), 7.31-7.38(1H, m),7.44(1H, d, J 3.0Hz), 8.06(1H, s)and 8.28(1H, s). 15 Mp226.9-227.7° C.;IRν_(max) Nujol)/cm⁻¹ 3331, 3111, 2925, 2854, 1638, 1574, 1488, 1460,1378, 1032 and 887; NMR δ_(H) 400MHz, DMSO)8.40(1H, s), 8.17(1H, s),7.75(1H, s), 7.21(1H, t, J7.2Hz), 7.10-7.00(3H, m), 6.88(1H, dd, J3.6,1.6Hz)and 5.39(2H, s); Anal. Calcd for C₁₇H₁₅N₅O · HCl · H₂O: C, 56.75;H, 5.04; N, 19.46. Found: C, 57.03; H, 5.06; N, 19.10. 16 40Mp202.3-202.4° C.; IRν_(max) Nujol)/cm⁻¹ 3408, 3327, 3212, 2924, 2854,1724, 1640, 1607, 1579, 1558, 1510, 1485 and 1448; NMR δ_(H) (400MHz,DMSO)8.30(1H, s), 8.06(1H, d, J1.2Hz), 7.87(1H, m), 7.81(1H, s),7.52-7.45(3H, m), 6.94(2H, s), 6.79(1H, dd, J3.6, 2.0Hz), 5.51(2H, s)and3.83(3H, s). 17 Mp239.2-239.4° C.; IRν_(max) Nujol)/cm⁻¹ 3318, 3136,2922, 2854, 1656, 1634, 1614, 1586, 1463, 1377, 1300 and 1148; NMR δ_(H)400MHz, DMSO)8.37(1H, s), 8.11(1H, s), 7.88(2H, d, J8.4Hz), 7.58 (1H, d,J3.4Hz), 7.42(2H, d, J8.3Hz), 6.83(1H, dd, J3.6, 1.7Hz), 5.6 (2H, s)and3.18(3H, s); Anal. Calcd for C₁₇H₁₅N₅O₃S · HCl · 0.5 H₂O: C, 49.22; H,4.13; N, 16.88. Found: C, 49.05; H, 3.93; N, 16.53. 18 NMR δ_(H) 400MHz,DMSO)8.37(1H, s), 8.16(1H, s), 7.73(1H, s), 7.27-7.16 (5H, m), 6.87(1H,dd, J3.4, 1.6Hz), 4.44(2H, d, J7.1Hz)and 3.16(2H, t, J7.2Hz); Anal.Calcd for C₁₇H₁₅N₅O · HCl: C, 59.74; H, 4.72; N, 20.48. Found: C, 59.46;H, 4.76; N, 20.11. 19 NMR δ_(H) 400MHz, DMSO)8.32(1H, s), 8.12(1H, d,J1.2Hz), 6.84 (1H, dd, J3.6, 2.0Hz), 4.04(2H, d, J7.6Hz), 1.92(1H, m),1.65-1.50 (5H, m)and 1.16-1.14(5H, m); Retention time 5.59 min. 20 99Mp306.0-306.3° C.; NMR δ_(H) 400MHz, DMSO)8.32(1H, s), 8.08 (1H, s),7.85(1H, m), 7.77(1H, s), 7.48(3H, m), 6.81(1H, dd, J3.6, 1.6Hz),7.0(2H, br s)and 5.50(2H, s); Retention time 0.62 min. 21 Mp191.4-191.5°C.; IRν_(max) Nujol)/cm⁻¹ 3456, 3328, 3121, 2924, 2854, 1662, 1633,1573, 1484, 1454, 1375 and 1032; NMR δ_(H) 400MHz, DMSO)8.33(1H, s),8.14(1H, s)7.66(1H, br s), 6.86(1H, br s), 4.89(1H, br m)and 1.45(6H, brm); Anal. Calcd for C₁₂H₁₃N₅O · HCl · 1.25 H₂O: C, 47.69; H, 5.50; N,23.17. Found: C, 47.90; H, 5.21; N, 23.00. 22 Mp219.0-219.4° C.;IRν_(max) Nujol)/cm⁻¹ 2924, 2854, 1644, 1574, 1461, 1377, 1328 and 1112;NMR δ_(H) 400MHz, DMSO)8.35(1H, s), 8.10(1H, s), 7.69(2H, d, J8.0Hz),7.55(1H, s), 7.39(2H, d, J8.0Hz), 6.82(1H, t, J1.6Hz)and 5.54(2H, s);Anal. Calcd for C₁₇H₁₂F₃N₅O · HCl · 0.5 H₂O: C, 50.44; H, 3.49; N,17.30. Found: C, 50.73; H, 3.23; N, 17.19. 23 Mp218° C.; NMR δ_(H)400MHz, DMSO)8.36(1H, s), 8.16(1H, s), 7.73 (1H, s), 6.87(1H, t,J1.8Hz), 4.19(2H, m), 7.80(2H, m), 1.32-1.23 (4H, m)and 0.84(3H, t,J6.8Hz); Anal. Calcd for C₁₄H₁₇N₅O · HCl: C, 54.63; H, 5.89; N, 22.74.Found: C, 54.55; H, 6.04; N, 22.44. 24 Mp235.5-236.2° C.; NMR δ_(H)400MHz, DMSO)8.20(1H, s), 8.12 (1H, s), 7.61(1H, d, J3.2Hz),7.50-7.43(1H, m), 7.14-7.11(2H, m), 6.83(1H, dd, J3.6, 1.6Hz)and5.44(2H, s); Anal. Calcd for C₁₆H₁₁F₂N₅O · HCl · 0.75 H₂O: C, 50.94; H,3.61; N, 18.56. Found: C, 50.96; H, 3.32; N, 18.20. 25 10 NMR δ_(H)400MHz, DMSO)5.61(2H, s), 6.79-6.83(1H, m), 7.52(1H, d, J3.5Hz),7.82(1H, dd, J8.0, 5.5Hz), 8.09(1H, s), 8.12(1H, s), 8.76 (1H, s); M/Z293(M + H)⁺. 26 41 Mp177.0-177.1° C.; IRν_(max) Nujol)/cm⁻¹ 3456, 3331,3211, 3142, 3121, 2726, 1731, 1651, 1587, 1559, 1488, 1462, 1377, 1235and 755; NMR δ_(H) 400MHz, DMSO)1.20(3H, t, J7.0Hz), 4.15(2H, q, J7.0Hz)5.06(2H, s), 6.78-6.81(1H, m), 6.94(2H, s), 7.44(1H, d, J3.5Hz),8.06(1H, s)and 8.28(1H, s); Anal. Calcd for C₁₃H₁₃N₅O₃: C, 54.35; H,4.56, N, 24.37. Found: C, 54.22; H, 4.58; N, 24.01. 27 95 Mp291.9-192.0°C.; IRν_(max) Nujol)/cm⁻¹ 3371, 3329, 3204, 3141, 2726, 1704, 1658,1579, 1456, 1378, 956 and 789; NMR δ_(H) 400MHz, DMSO)4.96(2H, s),6.78-6.80(1H, m), 6.92(2H, s), 7.44(1H, d, J3.5Hz), 8.05-8.07(1H, m),8.26(1H, s)and 13.09(1H, s); Anal. Calcd for C₁₁H₉N₅O₃ · 0.3 H₂O: C,49.93; H, 3.66, N, 26.46. Found: C, 50.22; H, 3.46; N, 26.12. 28 20Mp204.5° C.; IRν_(max) Nujol)/cm⁻¹ 3485, 3322, 2925, 1651, 1587, 1378,1232 and 709; NMR δ_(H) 400MHz, DMSO)5.14(2H, br s), 5.57(2H, s),7.01-7.14(3H, m), 7.20-7.31(2H, m), 7.59(1H, dd, J5.0, 1.0Hz), 7.98(1H,d, J3.5Hz)and 8.19(1H, s); Retention time 4.87 min 29 59 Mp249.8-249.9°C.; IRν_(max) Nujol)/cm⁻¹ 3441, 3292, 3058, 2645, 1705, 1668, 1630,1582, 1561, 1457, 1381 and 1215; NMR δ_(H) 400MHz, DMSO)5.25(2H, s),6.16-6.78(2H, s), 6.91-6.96(1H, m), 7.23 (1H, t, J7.0Hz), 7.88-7.99(3H,m), 8.24(1H, s), 8.37(1H, d, J5.0Hz), 8.49(1H, s)and 11.41(1H, s); Anal.Calcd for C₁₆H₁₃N₇O₃ · HCl · 3 H₂O: C, 43.49; H, 4.56; N, 22.19. Found:C, 43.60; H, 4.01; N, 21.95. 30 47 IRν_(max) Nujol)/cm⁻¹ 3604, 3342,3152, 3090, 2601, 1659, 1629, 1574, 1558, 1526 and 1460; NMR δ_(H)400MHz, DMSO)4.66-5.19(2H, s), 5.59(2H, s), 6.82-6.85(1H, m), 7.60(1H,d, J3.5Hz), 7.62-7.67(2H, m), 8.07-8.09(1H, m), 8.11(1H, d, J1.0Hz),8.14-8.17(1H, m), 8.39 (1H, s); Anal. Calcd for C₁₆H₁₂N₆O₃ · HCl · 0.75H₂O: C, 49.75; H, 3.78, N, 21.76. Found: C, 49.92; H, 3.39; N, 21.33. 31Mp190.9-191.7° C.; IRν_(max) Nujol)/cm⁻¹ 3407, 3171, 3089, 2923, 2854,1651, 1633, 1578, 1485, 1455 and 1377; NMR δ_(H) 400MHz, DMSO)8.40(1H,s), 8.17(1H, s), 7.76(1H, s), 7.30-7.15(5H, m), 6.88 (1H, dd, J3.5,1.6Hz), 4.23(2H, t, J7.0Hz), 2.60(2H, t, J7.3Hz)and 2.17-2.10(2H, m);Retention time 5.42 min. 32 94 NMR δ_(H) 400MHz, DMSO)4.70-5.44(2H, s),5.49(2H, s), 6.86(1H, s), 7.12(1H, s), 7.27(2H, t, J7.5Hz), 7.45(1H, t,J7.5Hz), 7.66(1H, d, J2.5Hz), 8.39(1H, s)and 9.48-10.63(2H, s); M/Z307(M + H)⁺. 33 19 IRν_(max) Nujol)/cm⁻¹ 3328, 3193, 2925, 2854, 1650,1598, 1561, 1513, 1456, 1430 and 1377; NMR δ_(H) 400MHz, DMSO)8.84(1H,d, J4.4Hz), 8.54(1H, s), 8.43(1H, d J8.0Hz), 8.04(1H, m), 7.60(1H, dd, J6.8, 5.2Hz), 7.34(1H, m), 7.22(1H, m), 7.13(1H, m)7.07(1H, m), 7.03 (2H,s)and 5.50(2H, s). 34 58 Mp276.8-277.2° C.; NMR δ_(H) 400MHz,DMSO)4.29(2H, d, J6.0Hz), 4.89(2H, s), 6.77-6.81(1H, m), 6.88(2H, s),7.21-7.37(5H, m), 7.44(1H, d, J3.5Hz), 8.04-8.07(1H, m), 8.26(1H, s)and8.50(1H, t, J6.0Hz). 35 58 Mp276.8-277.2° C.; NMR δ_(H) 400MHz,DMSO)4.29(2H, d, J6.0Hz), 4.89(2H, s), 6.77-6.81(1H, m), 6.88(2H, s),7.21-7.37(5H, m), 7.44(1H, d, J3.5Hz), 8.04-8.07(1H, m), 8.26(1H, s)and8.50(1H, t, J6.0Hz). 36 29 Mp279.9-281.0° C.; NMR δ_(H) 400MHz,DMSO)5.08(2H, s), 6.78-6.82 (1H, m), 6.90(2H, s), 7.13(1H, d), J8.0Hz),7.36(1H, t, J8.0Hz), 7.42-7.49(2H, m), 7.74-7.79(1H, m), 8.05-8.09(1H,m), 8.28(1H, s)and 10.52(1H, s). 37 49 Mp247.9-249.4° C.; NMR δ_(H)400MHz, DMSO)4.28(2H, d, J6.0Hz), 4.86(2H, s), 6.26(1H, d, J2.5Hz),6.38-6.41(1H, m), 6.77-6.80 (1H, m), 6.88(2H, s), 7.44(1H, d, J3.5Hz),7.57-7.60(1H, m), 8.04-8.07 (1H, m), 8.25(1H, s)and 8.52(1H, t, J5.5Hz).38 31 Mp200.0-200.1° C.; IRν_(max) Nujol)/cm⁻¹ 3473, 3181, 3078, 2923,1646, 1572, 1461, 1376, 792 and 768; NMR δ_(H) 400MHz, DMSO)5.19(2H, brs), 5.59(2H, s), 6.98-7.12(3H, m), 7.20-7.29(1H, m), 7.58(1H, d,J3.5Hz)and 8.59(1H, s); Retention time 4.64 min. 39 Mp223.2-225.1° C.;NMR δ_(H) 400MHz, DMSO)8.29(1H, s), 8.09 (1H, d, J1.2Hz), 7.58(1H, m),7.53(1H, d, J3.2Hz), 6.81(1H, dd, J 3.6, 2.0Hz), 6.41(1H, dd, J3.2,2.0Hz), 6.36(1H, d, J2.8Hz)and 5.40 (2H, s). 40 61 IRν_(max) Nujol)/cm⁻¹3495, 3321, 3210, 3118, 2727, 1635, 1604, 1579, 1478, 1464, 1390 and1175; NMR δ_(H) 400MHz, DMSO)2.36(3H, s), 6.78-6.79(1H, m),7.43-7.45(4H, m), 7.92(2H, d, J8.5Hz), 8.05(1H, s)and 8.52(1H, s). 41Mp218.7-219.5° C.; IRν_(max) Nujol)/cm⁻¹ 3495, 3321, 2925, 2854, 1615,1596, 1570, 1512, 1481, 1452, and 1377; NMR δ_(H) 400MHz, DMSO)8.34(1H,s), 7.46(1H, s), 7.34(1H, s), 7.21(2H, m), 7.13(1H, m), 7.05(1H, m),6.97(2H, br s), 5.47(2H, s)and 4.20(3H, s). 42 11 Mp250.5-251.2° C.;IRν_(max) Nujol)/cm⁻¹ 3483, 3354, 2924, 2854, 1616, 1601, 1575, 1503,1454, 1418 and 1377; NMR δ_(H) 400MHz, DMSO)13.08(1H, br s), 8.37(1H,s), 7.38-7.06(6H, m)6.72(2H, br s)and 5.48(2H, s). 43 59 Mp267.4-271.5°C.; IRν_(max) Nujol)/cm⁻¹ 3461, 3290, 3194, 1664, 1589, 1465, 1377,1291, 1235, 1157, 1014 and 795; NMR δ_(H) 400MHz, DMSO)3.71(3H, s),5.06(2H, s), 6.65(1H, dd, J8.0, 2.0Hz), 6.78-6.81 (1H, m), 6.89(2H, s),7.09(1H, d, J9.0Hz), 7.21(1H, d, J3.0Hz), 7.26-7.30(1H, m), 7.45(1H, d,J3.0Hz), 8.05-8.08(1H, m), 8.28 (1H, s)and 10.31(1H, s). 44 71Mp231.1-231.2° C.; IRν_(max) Nujol)/cm⁻¹ 3462, 3298, 3213, 3111, 1651,1586, 1558, 1487, 1456, 1377, 1280, 1169, 1009 and 765; NMR δ_(H)(400MHz, DMSO)2.72(2H, t, J7.0Hz), 3.24-3.35(2H, m), 4.80(2H, s),6.77-6.82(1H, m), 6.88(2H, s), 7.16-7.23(3H, m), 7.24-7.33 (2H, m),7.44(1H, d, J3.0Hz), 8.02-8.09(2H, m)and 8.25(1H, s). 45 15Mp276.2-278.5° C.; IRν_(max) Nujol)/cm⁻¹ 3448, 3288, 3199, 1669, 1588,1557, 1456, 1378, 1309, 1106, 888 and 757; NMR δ_(H) 400MHz,DMSO)5.15(2H, s), 6.76-6.83(1H, m), 6.90(2H, s), 7.11-7.20(2H, m),7.23-7.32(1H, m), 7.42-7.48(1H, m), 7.83-7.93(1H, m), 8.04-8.09 (1H, m),8.28(1H, s)and 10.12(1H, s). 46 22 NMR δ_(H) 400MHz, DMSO)8.39(1H, m),8.29(1H, s), 8.06(1H, d, J 1.2Hz), 7.72-7.68(2H, m), 7.45-7.31(2H, m),6.92(2H, s), 6.79(1H, dd, J3.2, 1.6Hz), 5.47(2H, s)and 2.74(3H, d,J4.8Hz); Anal. Calcd for C₁₈H₁₆N₆O₂ · 0.5 H₂O: C, 60.50; H, 4.79; N,23.52. Found: C, 60.32; H, 4.63; N, 23.50. 47 33 NMR δ_(H) 400MHz,DMSO)8.29(1H, s), 8.06(1H, s), 7.44(1H, d, J3.4Hz), 7.40-7.20(4H, m),6.92(2H, s), 6.79(1H, dd, J3.5, 1.9Hz)5.46 (2H, s), 2.94(3H, br s)and2.85(3H, br s). 48 75 NMR δ_(H) 400MHz, DMSO)3.79(3H, s), 4.25(2H, d,J6.0Hz), 4.90 (2H, s), 6.75-6.81(1H, m), 6.84-7.01(4H, m), 7.18-7.28(2H,m), 7.44(1H, d, J3.5Hz), 8.06(1H, s), 8.27(1H, s), 8.29(1H, t, J6.0Hz).Anal. Calcd. for C₁₉H₁₈N₆O₃ · 0.5 H₂O: C, 58.91; H, 4.94; N, 21.69.Found: C, 60.20; H, 5.34; N, 21.33; M/Z 379(M + H)⁺. 49 75 NMR δ_(H)400MHz, DMSO)4.33(2H, d, J5.0Hz), 4.90(2H, s), 6.79 (1H, s), 6.89(2H,s), 7.11-7.23(2H, m), 7.26-7.40(2H, m), 7.44(1H, d, J3.0Hz), 8.06(1H,s), 8.27(1H, s)and 8.52(1H, t, J5.5Hz); M/Z 367(M + H)⁺. 50 89 Mp.265.8° C.; IRν_(max) Nujol)/cm⁻¹ 3360, 3290, 3147, 2924, 2854, 1637,1608, 1575, 1497, 1465 and 1377; NMR δ_(H) 400MHz, DMSO)13.8 (1H, br s),8.45(1H, s), 8.02(1H, s), 7.22(1H, br s), 7.13(4H, s), 5.39 (2H, s)and2.26(3H, s). 51 18 Mp. 287.9° C.; NMR δ_(H) 400MHz, DMSO)8.77(1H, br s),8.40(1H, s), 7.37-7.11(4H, m)and 5.50(2H, s). 52 80 NMR δ_(H) 400MHz,DMSO)8.35(1H, s), 8.14(1H, dd, J8.1, 1.1Hz), 8.07(1H, d, J1.2Hz),7.67-7.56(2H, m), 7.47(1H, d, J3.5Hz), 6.95 (2H, s), 6.81-6.79(2H,m)and(5.80(2H, s); Anal. Calcd for C₁₆H₁₂N₆O₃ · 0.3 H₂O: C, 56.24; H,3.72; N, 24.59. Found: C, 56.41; H, 3.48; N, 24.15. 53 IRν_(max)Nujol)/cm⁻¹ 2924, 2854, 1605, 1581, 1465, 1377, 1156 and 1018; NMR δ_(H)400MHz, DMSO)12.0(1H, br s), 10.39(1H, br s), 8.52 (1H, s), 8.16(1H, s),7.81(2H, br s), 7.75(1H, d, J4.0Hz), 7.60(1H, s), 7.38(1H, d, J2.4Hz),7.23(1H, t, J7.6Hz), 7.05-6.85(5H, m)and 5.49(2H, s); Anal. Calcd forC₂₀H₁₆N₆O₃S₂ · 0.4 H₂O: C, 47.57; H, 3.13; N, 13.87. Found: C, 47.70; H,3.20; N, 13.53. 54 22 NMR δ_(H) 400MHz, DMSO)5.36(2H, s), 6.78-6.82(1H,m), 6.87(1H, s), 6.89-6.95(2H, m), 6.98-7.04(3H, m), 7.21(1H, t,J8.0Hz), 7.38-7.40 (1H, m), 7.46(1H, d, J3.5Hz), 7.81(1H, dd, J5.0,1.0Hz), 8.07 (1H, s), 8.28(1H, s)and 10.39(1H, s); M/Z 453(M + H)⁺. 5540 Mp245.3-246.1° C.; IRν_(max) Nujol)/cm⁻¹ 3666, 2922, 1638, 1460,1378, 1229 and 757; NMR δ_(H) 400MHz, DMSO)5.49(2H, s), 7.12-7.28(3H,m), 7.31-7.42(2H, m), 8.06(1H, d, J2.0Hz)and 8.53(1H, s); Retention time2.10 min. 56 IRν_(max) Nujol)/cm⁻¹ 3600-2500 br, 2921, 2853, 1659, 1633,1574, 1556, 1462, 1378 and 1031; NMR δ_(H) 400MHz, DMSO)8.38(1H, s),8.13(1H, d, J1.2Hz), 7.37-7.29(2H, m), 7.12(1H, m), 6.88-6.84 (2H, m)and5.54(2H, s). 57 6 NMR δ_(H) 400MHz, DMSO)3.68(3H, s), 5.49(2H, s),6.60(1H, d, J7.5Hz), 6.79-6.82(1H, m), 6.91(2H, s), 7.02-7.09(1H, m),7.18(2H, d, J4.5Hz), 7.47(1H, d, J3.5Hz), 7.23(1H, s), 7.84(1H, s),8.07(1H, s), 8.31(1H, s)and 10.13(1H, s); M/Z 451(M + H)⁺. 58 14 NMRδ_(H) 400MHz, DMSO)8.73(1H, br s), 8.40(1H, s), 8.15(1H, m), 8.08(1H,s), 7.64(1H, d, J5.1Hz)and 5.61(2H, s). 59 5 Mp278.5-279.0° C.; NMRδ_(H) 400MHz, DMSO)8.44(1H, s), 8.15 (1H, m), 8.08(1H, s), 7.97(1H, d,J2.3Hz), 7.10(1H, s), 7.10(2H, br s) and 6.00(2H, s). 60 22Mp193.3-193.4° C.; IRν_(max) Nujol)/cm⁻¹ 3289, 2934, 1661, 1642, 1582,1514, 1460 and 1377; NMR δ_(H) 400MHz, DMSO)8.76(1H, s), 8.40(1H, s),7.44(1H, t, J7.6Hz), 7.25(2H, m)7.07(1H, s)and 5.50 (2H, s). 61 25Mp193.3-193.4° C.; NMR δ_(H) 400MHz, DMSO)5.61(2H, s), 7.17 (2H, br s),7.61-7.67(2H, m), 8.07-8.11(2H, m), 8.12-8.19(1H, m), 8.23(1H, d,J3.0Hz)and 8.43(1H, s); Retention time 4.70 min. 62 93 Mp177.8-178.3°C.; IRν_(max) Nujol)/cm⁻¹ 3302, 2925, 1634, 1462, 1377, 774 and 778; NMRδ_(H) 400MHz, DMSO)5.50(2H, s), 7.08(1H, s), 7.23-7.31(2H, m), 7.45(1H,t, J7.5Hz), 8.09(1H, d, J3.0Hz), 8.22 (1H, d, J3.0Hz)and 8.41(1H, s);Retention time 1.75 min. 63 67 IRν_(max) Nujol)/cm⁻¹ 3162, 2920, 1551,1574, 1464, 1378, 1072 and 766; NMR δ_(H) 400MHz, DMSO)8.51(1H, s),8.04(1H, d, J2.5Hz), 7.44 (1H, t, J8.0Hz), 7.31(1H, br s), 7.27-7.20(2H,m), 7.10(1H, s)and 5.49(2H, s). 64 81 Mp171-172° C.; IRν_(max)Nujol)/cm⁻¹ 3252, 2922, 1667, 1619, 1466, 1378, 1261, 1169, 769 and 751;NMR δ_(H) 400MHz, DMSO)8.59(1H, s), 8.10(1H, d, J2.5Hz), 7.51(1H, br s),7.25(1H, t, J8.0Hz), 6.90-6.82 (2H, m), 6.82-6.77(1H, d, J8.0Hz),5.43(2H, s)and 3.72(3H, s). 65 82 IRν_(max) Nujol)/cm⁻¹ 3318, 2923,1640, 1455, 1455, 1378 and 750; NMR δ_(H) 400MHz, DMSO)11.13(1H, br s),8.23(1H, s), 8.05(1H, d, J1.0Hz), 7.43(1H, d, J3.5Hz), 7.34-7.28(2H, m),7.00(1H, t, J7.0Hz), 6.89(2H, br s), 6.78(1H, dd, J3.5, 2.0Hz), 6.73(1H,d, J6.5Hz), 6.53-6.49 (1H, m)and 5.63(2H, s). 66 NMR δ_(H) 400MHz,DMSO)8.25(1H, s), 8.06-8.04(1H, m), 7.99(1H, d, J8.5Hz), 7.68(1H, d,J3.5Hz), 7.43(1H, d, J3.5Hz), 7.26(1H, t, J 7.5Hz), 6.99(1H, d, J6.5Hz),6.93(2H, br s), 6.86(1H, d, J4.0Hz), 6.79-6.77(1H, m), 5.65(2H, s)and1.61(9H, s).

[0223] Adenosine Receptor Binding

[0224] Binding Affinities at hA_(2A) Receptors

[0225] The compounds were examined in an assay measuring in vitrobinding to human adenosine A_(2A) receptors by determining thedisplacement of the adenosine A_(2A) receptor selective radioligand[³H]-CGS 21680 using standard techniques. The results are summarised inTable 3. TABLE 3 Example K_(i) nM) Example 11 9 Example 12 2 Example 142 Example 15 2 Example 22 6 Example 24 2 Example 28 5 Example 30 4Example 31 2 Example 32 4 Example 33 12 Example 51 71 Example 55 16Example 56 8

[0226] Evaluation of Potential Anti-Parkinsonian Activity In Vivo

[0227] Haloperidol-Induced Hypolocomotion Model

[0228] It has previously been demonstrated that adenosine antagonists,such as theophylline, can reverse the behavioural depressant effects ofdopamine antagonists, such as haloperidol, in rodents (Mandhane S. N. etal., Adenosine A₂ receptors modulate haloperidol-induced catalepsy inrats. Eur. J. Pharmacol. 1997, 328, 135-141). This approach is alsoconsidered a valid method for screening drugs with potentialantiparkinsonian effects. Thus, the ability of novel adenosineantagonists to block haloperidol-induced deficits in locomotor activityin mice can be used to assess both in vivo and potentialantiparkinsonian efficacy.

[0229] Method

[0230] Female TO mice (25-30 g) obtained from TUCK, UK, are used for allexperiments. Animals are housed in groups of 8 [cage size—40 (width)×40(length)×20 (height)cm] under 12 hr light/dark cycle (lights on 08:00hr), in a temperature (20±2° C.) and humidity (55±15%) controlledenvironment. Animals have free access to food and water, and are allowedat least 7 days to acclimatize after delivery before experimental use.

[0231] Drugs

[0232] Liquid injectable haloperidol (1 ml Serenance ampoules from BakerNorton, Harlow, Essex, each containing haloperidol BP 5 mg, batch #P424) are diluted to a final concentration of 0.02 mg/ml using saline.Test compounds are typically prepared as aqueous suspensions in 8%Tween. All compounds are administered intraperitoneally in a volume of10 ml/kg.

[0233] Procedure

[0234] 1.5 hours before testing, mice are administered 0.2 mg/kghaloperidol, a dose that reduces baseline locomotor activity by at least50%. Test substances are typically administered 5-60 minutes prior totesting. The animals are then placed individually into clean, clearpolycarbonate cages [20 (width)×40 (length)×20 (height) cm , with a flatperforated, Perspex lid]. Horizontal locomotor activity is determined byplacing the cages within a frame containing a 3×6 array of photocellslinked to a computer, which tabulates beam breaks. Mice are leftundisturbed to explore for 1 hour, and the number of beams breaks madeduring this period serves as a record of locomotor activity which iscompared with data for control animals for statistically significantdifferences.

[0235] 6-OHDA Model

[0236] Parkinson's disease is a progressive neurodegenerative disordercharacterised by symptoms of muscle rigidity, tremor, paucity ofmovement (hypokinesia), and postural instability. It has beenestablished for some time that the primary deficit in PD is a loss ofdopaminergic neurones in the substantia nigra which project to thestriatum, and indeed a substantial proportion of striatal dopamine islost (ca 80-85%) before symptoms are observed. The loss of striataldopamine results in abnormal activity of the basal ganglia, a series ofnuclei which regulate smooth and well co-ordinated movement (Blandini F.et al., Glutamate and Parkinson's Disease. Mol. Neurobiol. 1996, 12,73-94). The neurochemical deficits seen in Parkinson's disease can bereproduced by local injection of the dopaminergic neurotoxin6-hydroxydopamine into brain regions containing either the cell bodiesor axonal fibres of the nigrostriatal neurones.

[0237] By unilaterally lesioning the nigrostriatal pathway on onlyone-side of the brain, a behavioural asymmetry in movement inhibition isobserved. Although unilaterally-lesioned animals are still mobile andcapable of self maintenance, the remaining dopamine-sensitive neuroneson the lesioned side become supersenstive to stimulation. This isdemonstrated by the observation that following systemic administrationof dopamine agonists, such as apomorphine, animals show a pronouncedrotation in a direction contralateral to the side of lesioning. Theability of compounds to induce contralateral rotations in 6-OHDAlesioned rats has proven to be a sensitive model to predict drugefficacy in the treatment of Parkinson's Disease.

[0238] Animals

[0239] Male Sprague-Dawley rats, obtained from Charles River, are usedfor all experiments. Animals are housed in groups of 5 under 12 hrlight/dark cycle (lights on 08:00 hr), in a temperature (20±2° C.) andhumidity (55±15%) controlled environment. Animals have free access tofood and water, and are allowed at least 7 days to acclimatize afterdelivery before experimental use.

[0240] Drugs

[0241] Ascorbic acid, desipramine, 6-OHDA and apomorphine(Sigma-Aldrich, Poole, UK). 6-OHDA is freshly prepared as a solution in0.2% ascorbate at a concentration of 4 mg/mL prior to surgery.Desipramine is dissolved in warm saline, and administered in a volume of1 ml/kg. Apomorphine is dissolved in 0.02% ascorbate and administered ina volume of 2 mL/kg. Test compounds are suspended in 8% Tween andinjected in a volume of 2 mL/kg.

[0242] Surgery

[0243] 15 minutes prior to surgery, animals are given an intraperitonealinjection of the noradrenergic uptake inhibitor desipramine (25 mg/kg)to prevent damage to non-dopamine neurones. Animals are then placed inan anaesthetic chamber and anaesthetised using a mixture of oxygen andisoflurane. Once unconscious, the animals are transferred to astereotaxic frame, where anaesthesia is maintained through a mask. Thetop of the animal's head is shaved and sterilised using an iodinesolution. Once dry, a 2 cm long incision is made along the midline ofthe scalp and the skin retracted and clipped back to expose the skull. Asmall hole is then drilled through the skill above the injection site.In order to lesion the nigrostriatal pathway, the injection cannula isslowly lowered to position above the right medial forebrain bundle at−3.2 mm anterior posterior, −1.5 mm medial lateral from bregma, and to adepth of 7.2 mm below the duramater. 2 minutes after lowing the cannula,2 μL of 6-OHDA is infused at a rate of 0.5 μL/min over 4 minutes,yeilding a final dose of 8 μg. The cannula is then left in place for afurther 5 minutes to facilitate diffusion before being slowly withdrawn.The skin is then sutured shut using Ethicon W501 Mersilk, and the animalremoved from the strereotaxic frame and returned to its homecage. Therats are allowed 2 weeks to recover from surgery before behaviouraltesting.

[0244] Apparatus

[0245] Rotational behaviour is measured using an eight station rotametersystem provided by Med Associates, San Diego, USA. Each station iscomprised of a stainless steel bowl (45 cm diameter×15 cm high) enclosedin a transparent Plexiglas cover running around the edge of the bowl,and extending to a height of 29 cm. To assess rotation, rats are placedin cloth jacket attached to a spring tether connected to opticalrotameter positioned above the bowl, which assesses movement to the leftor right either as partial (45°) or full (360°) rotations. All eightstations are interfaced to a computer that tabulated data.

[0246] Procedure

[0247] To reduce stress during drug testing, rats are initiallyhabituated to the apparatus for 15 minutes on four consecutive days. Onthe test day, rats are given an intraperitoneal injection of testcompound 30 minutes prior to testing. immediately prior to testing,animals are given a subcutaneous injection of a subthreshold dose ofapomorphine, then placed in the harness and the number of rotationsrecorded for one hour. The total number of full contralatral rotationsduring the hour test period serves as an index of antiparkinsonian drugefficacy.

1. Use of a compound of formula (I):

wherein R₁ is selected from alkyl, alkoxy, aryloxy, alkylthio, arylthio, aryl, halogen, CN, NR₆R₇, NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈ and NR₅SO₂R₈; R₂ is selected from heteroaryl attached via an unsaturated carbon; R₃ is selected from H, alkyl, halogen, OR₅, SR₅ and NR₆R₇; R₄ is selected from H, acyclic alkyl, CONR₆R₇, CONR₅NR₆R₇, COR₆, CO₂R₈ and SO₂R₈; R₅, R₆ and R₇ are independently selected from H, alkyl and aryl, or where R₆ and R₇ are in an NR₆R₇ group, R₆ and R₇ may be linked to form a heterocyclic group, or where R₅, R₆ and R₇ are in a (CONR₅NR₆R₇) group, R₅ and R₆ may be linked to form a heterocyclic group; and R₈ is selected from alkyl and aryl, or a pharmaceutically acceptable salt or prodrug thereof, in the manufacture of a medicament for the treatment or prevention of a disorder in which the blocking of purine receptors may be beneficial.
 2. Use according to claim 1 wherein R₁ is selected from alkyl, alkoxy, thioalkyl, NR₆R₇, NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈ and NR₅SO₂R₈.
 3. Use according to claim 1 wherein R₁ is selected from NR₆R₇, NR₅COR₆, NR₅CONR₆R₇, NR₅CO₂R₈ and NR₅SO₂R₈.
 4. Use according to claim 1 wherein R₁ is selected from NR₆R₇.
 5. Use according to claim 1 wherein R₁ is selected from NH₂.
 6. Use according to claim 1 wherein R₁ is selected from NR₅CONR₆R₇, NR₅COR₆, NR₅CO₂R₈ and NR₅SO₂R₈, and R₅ is H or alkyl.
 7. Use according to claim 1 wherein R₁ is selected from NR₅CONR₆R₇, NR₅COR₆, NR₅CO₂R₈ and NR₅SO₂R₈, and R₅ is H.
 8. Use according to claim 1 wherein R₁ is selected from haloalkyl and arylalkyl.
 9. Use according to any preceding claim wherein R₂ is a 5- or 6-membered monocyclic heteroaryl group.
 10. Use according to any preceding claim wherein R₂ is a heteroaryl group which is attached to the pyrimidine ring of formula (I) such that a heteroatom is adjacent to said unsaturated carbon atom attached to the pyrimidine ring.
 11. Use according to any preceding claim wherein R₂ is an N, O or S-containing heteroaryl group.
 12. Use according to any of claims 1 to 11 wherein R₂ is unsubstituted in at least one ortho position.
 13. Use according to any of claims 1 to 11 wherein R₂ is unsubstituted at both ortho positions.
 14. Use according to any preceding claim wherein R₂ is selected from furyl, thienyl, pyridyl, pyrazolyl and thiazolyl.
 15. Use according to any preceding claim wherein R₂ is selected from 2-furyl, 2-thienyl, 2-thiazolyl, 3-pyrazolyl and 2-pyridyl.
 16. Use according to any preceding claim wherein R₂ is 2-furyl.
 17. Use according to any preceding claim wherein R₃ is hydrogen.
 18. Use according to any of claims 1 to 17 wherein R₄ is selected from H and substituted acyclic alkyl.
 19. Use according to claim 18 wherein R₄ is acyclic alkyl substituted by susbtituted or unsubstituted aryl, cycloalkyl, non-aromatic heterocyclyl, CO₂R₅, CONR₆R₇, CONR₅NR₆R₇ and C(═NR₅)NR₆R₇.
 20. Use according to claim 19 wherein R₄ is acyclic alkyl substituted by substituted or unsubstituted aryl or CONR₆R₇.
 21. Use according to claim 20 wherein R₄ is methyl substituted by substituted or unsubstituted aryl or CONR₆R₇.
 22. Use according to any of claims 1 to 17 wherein R₄ is selected from (CR₉R₁₀)_(n)R₁₁ wherein n is 1 to 6, R₉ and R₁₀ are independently selected from H, alkyl and aryl, and R₁₁ is selected from substituted and unsubstituted aryl, cycloalkyl, non-aromatic heterocyclic, CO₂R₅, CONR₆R₇, CONR₅NR₆R₇ and C(═NR₅)NR₆R₇.
 23. Use according to claim 22 wherein n is
 1. 24. Use according to claim 22 or 23 wherein R₉ and R₁₀ are independendy selected from H and alkyl, preferably H.
 25. Use according to claim 22, 23 or 24 wherein R₁₁ is selected from substituted or unsubstituted aryl and CONR₆R₇.
 26. Use according to any of claims 22 to 25 wherein R₁₁ is a substituted aryl group represented by the formula Ar(R₁₂)_(a)(R₁₃)_(b)(R₁₄)_(c) wherein Ar is an aryl group; wherein R₁₂, R₁₃ and R₁₄ are substituent group(s), the same or different; and wherein a, b and c are 0 or 1 such that a+b+c≧1.
 27. Use according to claim 26 wherein R₁₂, R₁₃ and R₁₄ are independently selected from NR₆R₇, alkyl, alkoxy, halogen, NO₂, CN, hydroxy, NHOH, CHO, CONR₆R₇, CO₂R₅, NR₅COR₆, NR₅CO₂R₈, NR₅SO₂R₈, OCO₂R₈ and aryl.
 28. Use according to claim 26 wherein R₁₂, R₁₃ and R₁₄ are independently selected from NR₆R₇, alkyl and halogen.
 29. Use according to claim 27 or 28 wherein R₁₂, R₁₃ and R₁₄ are independently selected from alkyl, and said alkyl is substituted alkyl and is selected from alkoxyalkyl, hydroxyalkyl, aminoalkyl and haloalkyl.
 30. Use according to claim 27 or 28 wherein R₁₂, R₁₃ and R₁₄ are independently selected from unsubstituted alkyl, NH₂ and fluoro.
 31. Use according to any of claims 19 to 30 wherein said substituted or unsubstituted aryl group is substituted or unsubstituted phenyl, thienyl, furyl, pyridyl or indolyl.
 32. Use according to claim 31 wherein said substituted or unsubstituted aryl group is substituted and unsubstituted phenyl, thienyl, furyl or pyridyl.
 33. Use according to claim 22, 23 or 24 wherein R₁₁ is selected from CONR₆R₇, R₆ is H and R₇ is selected from H, unsubstituted alkyl, arylalkyl and aryl.
 34. Use according to any one of claims 1 to 17 wherein R₄ is selected from CONR₆R₇, R₆ is H and R₇ is selected from arylalkyl.
 35. Use according to claim 34 wherein R₇ is selected from arylmethyl.
 36. Use according to any preceding claim wherein R₅ to R₈ are independently selected from lower alkyl.
 37. Use according to claim 1 wherein R₁ is NH₂, R₂ is 2-furyl, R₃ is H and R₄ is arylmethyl.
 38. Use according to claim 1 wherein the compound of formula (I) is selected from Examples 1 to 66 disclosed herein.
 39. Use according to claim 1 wherein the compound of formula (I) is selected from: 4-(2-furyl)-1-(3-methoxybenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; 1-(2-fluorobenzyl)-4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; 4-(2-furyl)-1-(3-methylbenzyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; 1-(2,6-difluorobenzyl)4-(2-furyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; 4-(2-furyl)-1-(3-phenylpropyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine; and 1-(2-fluorobenzyl)-4-(2-pyridyl)-1H-pyrazolo[3,4-d]pyrimidine-6-amine.
 40. A method of treating or preventing a disorder in which the blocking of purine receptors may be beneficial comprising administration to a subject in need of such treatment an effective dose of a compound as set out in any one of claims 1 to 39 or a pharmaceutically acceptable salt thereof.
 41. A use or method according to any one of claims 1 to 40 wherein the disorder is caused by the hyperfunctioning of purine receptors.
 42. A use or method according to any one of claims 1 to 41 wherein the purine receptors are adenosine receptors.
 43. A use or method according to claim 42 wherein the adenosine receptors are A_(2A) receptors.
 44. Use or method according to any preceding claim wherein the disorder is a movement disorder.
 45. A use or method according to claim 44 wherein the movement disorder is Parkinson's disease.
 46. A use or method according to claim 45 for treatment of drug-induced Parkinsonism, post-encephalitic Parkinsonism, Parkinsonism induced by poisoning or post-traumatic Parkinson's disease.
 47. A use or method according to claim 44 wherein the movement disorder is progressive supernuclear palsy, Huntingtons disease, multiple system atrophy, corticobasal degeneration, Wilsons disease, Hallerrorden-Spatz disease, progressive pallidal atrophy, Dopa-responsive dystonia-Parkinsonism, spasticity or other disorders of the basal ganglia which result in dyskinesias.
 48. A use or method according to any one of claims 44 to 47 wherein the compound of formula (I) is in combination with one or more additional drugs useful in the treatment of movement disorders, the components being in the same formulation or in separate formulations for administration simultaneously or sequentially.
 49. A use or method according to claim 48 wherein said additional drug(s) useful in the treatment of movement disorders is/are a drug useful in the treatment of Parkinson's disease.
 50. A use or method according to claim 48 or 49 wherein the or one of the additional drugs is L-DOPA or a dopamine agonist.
 51. A use or method according to any one of claims 1 to 43 wherein said disorder is depression, cognitive or memory impairment, acute or chronic pain, ADHD or narcolepsy.
 52. A use or method according to claim 51 wherein said cognitive or memory impairment disorder is Alzheimer's Disease.
 53. Use of a compound as set out in any one of claims 1 to 39 or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for neuroprotection in a subject.
 54. A method of neuroprotection comprising administration to a subject in need of such treatment an effective dose of a compound as set out in any one of claims 1 to 39 or a pharmaceutically acceptable salt thereof.
 55. A use or method according to claim 53 or 54 wherein said medicament or said method is for neuroprotection in a subject suffering from or at risk from a neurodegenerative disorder.
 56. A use or method according to claim 55 wherein said neurodegenerative disorder is a movement disorder.
 57. A use or method according to claim 56 wherein said movement disorder is a disorder as set out in claim 45, 46 or
 47. 58. A use or method according to any one of claims 1 to 57 wherein the subject is human.
 59. A compound according to any one of claims 1 to 39, or a pharmaceutically acceptable salt thereof, for use in therapy.
 60. A compound according to any one of claims 1 to 39, or a pharmaceutically acceptable salt or prodrug thereof, per se, other than compounds wherein R₂ is selected from pyrazolopyrimidines.
 61. A compound according to claim 60 wherein the compound is selected from those wherein R₂ is a 5- or 6-membered monocyclic heteroaryl group. 